Obsessive Compulsive Disorder

“A MINI PROJECT REPORT” OF PAPER-8 “Psychotherapy for Mental Disorders” ON TOPIC: OBSESSIVE COMPULSIVE DISORDER Submitted for the partial fulfilment of the Degree of Masters in Psychotherapy By: Ms.

Roshni Sondhi Roll No. : IIH/048/PG/PTH/2009J Second Year THE GLOBAL OPEN UNIVERSITY NAGALAND TABLE OF CONTENTS Title page1 Table of contents2 Introduction4 Features of obsessions and compulsions5 The psychodynamic perspective8 The behavioural perspective9 The cognitive perspective11 The biological perspective12Diagnosis and phenomenology of OCD15 Symptom subtypes18 Comorbidity, differential diagnosis and the obsessive compulsive spectrum disorders21 Epidemiology25 Biological contributions27 Biochemistry and neuropharmacology28 Neuropsychology31 Neuroanatomy33 A neurodevelopmental model of OCD40 PANDAS42 Cognitive contributions44 Treatment based on cognitive theories52 Conclusion54 References57 INTRODUCTION The past two decades were characterized by enormous advancement in understanding the nature of mental illness.In particular, findings from basic neuroscience raised the possibility of eventually unravelling the pathophysiology of mental disorders. Similarly, cognitive theories have taken on increasing prominence in explanations for maladaptive psychological functioning.

With respect to the anxiety disorders in general, and obsessive compulsive disorder in particular, there has been a virtual explosion of research since the introduction of DSM-III in 1980; much of which is biological and cognitive. Obsessions are persistent thoughts, ideas, impulses, or images that seem to invade a person’s consciousness.Compulsions are repetitive and rigid behaviours or mental acts that people feel they must perform in order to prevent or reduce anxiety. Minor obsessions and compulsions are familiar to almost everyone. You may find yourself filled with thoughts about an upcoming performance or exam, or keep wondering whether you forgot to turn off the stove or lock the door. You may feel better when you avoid stepping on cracks, turn away from black cats, or arrange your closet in a particular manner. Minor obsessions and compulsions can play a helpful role in life.Little rituals often calm us during times of stress.

A person who repeatedly hums a tune or taps his or her fingers during a test may be releasing tension and thus improving performance. Many people find it comforting to repeat religious or cultural rituals, such as touching a mezuzah, sprinkling holy water, or fingering rosary beads. According to DSM-IV-TR, a diagnosis of obsessive-compulsive disorder is called for when obsessions or compulsions feel excessive or unreasonable, cause great distress, take up much time, or interfere with daily functions.The disorder is classified as an anxiety disorder because the obsessions cause intense anxiety, while the compulsions are aimed at preventing or reducing anxiety. In addition, anxiety rises if individuals try to resist their obsessions or compulsions. Georgia, a woman with this disorder, observed: “I can’t get to sleep unless I am sure everything in the house is in its proper place so that when I get up in the morning, the house is organized.

I work like mad to set everything straight before I go to bed, but, when I get up in the morning, I can think of a thousand things that I ought to do….I can’t stand to know something needs doing and I haven’t done it” (McNeil, 1967, pp.

26-28). Georgia’s family was no less affected by her rigid pattern, as these comments by her husband indicate: Sometimes I think she never sleeps. I got up one night at 4 a. m. and there she was doing the laundry downstairs. …

If I forget to leave my dirty shoes outside the back door she gives me a look like I had just crapped in the middle of an operating room. I stay out of the house a lot and I’m about half-stoned when I do have to be home.She even made us get rid of the dog because she said he was always filthy. When we used to have people over for supper she would jitterbug around everybody till they couldn’t digest their food.

I hated to call them up and ask them over because I could always hear them hem and haw and make up excuses not to come over. Even the kids are walking down the street nervous about getting dirt on them. I’m going out of my mind but you can’t talk to her. She just blows up and spends twice as much time cleaning things.We have guys in to wash the walls so often I think the house is going to fall down from being scrubbed all the time.

(McNeil, 1967,pp. 2fr-27) Between 1 and 2 percent of the people in the United States and other countries throughout the world suffer from obsessive-compulsive disorder in any given year (Bjorgvinsson & Hart, 2008; Wetherell et aI. 2006; Kessler et aI.

2005). Between 2 and 3 percent develop the disorder at some point during their lives. It is equally common in men and women and among people of different races and ethnic groups.The disorder usually begins by young adulthood and typically persists for many years, although its symptoms and their severity may fluctuate over time (Angst et al. , 2004). It is estimated that more than 40 percent of people with obsessive-compulsive disorder seek treatment (Kessler et aI. , 1999, 1994). FEATURES OF OBSESSIONS AND COMPULSIONS Obsessions are thoughts that feel both intrusive (“ego dystonic”) and foreign (“ego alien”) to the people who experience them.

Attempts to ignore or resist these thoughts may arouse even more anxiety, and before long they come back more strongly than ever.Like Georgia, people with obsessions are quite aware that their thoughts are excessive. Obsessions often take the form of obsessive wishes (for example, repeated wishes that one’s spouse would die), impulses (repeated urges to yell out obscenities at work or in church), images (fleeting visions of forbidden sexual scenes), ideas (notions that germs are lurking everywhere), or doubts (concerns that one has made or will make a wrong decision).

In the following excerpt, a clinician describes a 20-year-old college junior who was plagued by obsessive doubts.He now spent hours each night “rehashing” the day’s events, especially interactions with friends and teachers, endlessly making “right” in his mind any and all regrets. He likened the process to playing a videotape of each event over and over again in his mind, asking himself if he had behaved properly and telling himself that he had done his best, or had said the right thing every step of the way. He would do this while sitting at his desk, supposedly studying; and it was not unusual for him to look at the clock after such a period of rumination and note that, to his surprise, two or three hours had elapsed. Spitzeretal. , 1981, pp. 20-21) Certain basic themes run through the thoughts of most people troubled by obsessive thinking (Abramowitz, McKay, & Taylor, 2008; APA, 2000). The most common theme appears to be dirt or contamination (Tolin & Meunier, 2008).

Other common ones are violence and aggression, orderliness, religion, and sexuality. The prevalence of such themes may vary from culture to culture. Religious obsessions, for example, seem to be more common in cultures or countries with strict moral codes and religious values (Bjorgvinsson & Hart, 2008; Rasmussen & Eisen, 1992).Compulsions are similar to obsessions in many ways. For example, although compulsive behaviours are technically under voluntary control, the people who feel they must do them have little sense of choice in the matter.

Most of these individuals recognize that their behaviour is unreasonable, but they believe at the same time something terrible will happen if they don’t perform the compulsions. After performing a compulsive act, they usually feel less anxious for a short while. For some people the compulsive acts develop into detailed rituals.They must go through the ritual in exactly the same way every time, according to certain rules.

Like obsessions, compulsions take various forms. Cleaning compulsions are very common. Like Georgia, people with these compulsions feel compelled to keep cleaning themselves, their clothing, or their homes. The cleaning may follow ritualistic rules and be repeated dozens or hundreds of times a day. People with checking compulsions check the same items over and over-door locks, gas taps, important papers-to make sure that all is as it should be (Radomsky et al. 2008). Another common compulsion is the constant effort to seek order or balance (Coles ; Pietrefesa, 2008). People with this compulsion keep placing certain items (clothing, books, foods) in perfect order in accordance with strict rules.

Touching, verbal, and counting compulsions are also common. People with touching compulsions repeatedly touch or avoid touching certain items. Individuals with verbal rituals feel compelled to repeat expressions, phrases, or chants. And those with counting compulsions constantly count things they see around them.Although some people with obsessive-compulsive disorder experience obsessions only or compulsions only, most of them experience both (Clark ; Guyitt, 2008). In fact, compulsive acts are often a response to obsessive thoughts (Foa ; Franklin, 2001). One study found that in most cases, compulsions seemed to represent a yielding to obsessive doubts, ideas, or urges (Akhtar et al. , 1975).

A woman who keeps doubting that her house is secure may yield to that obsessive doubt by repeatedly checking locks and gas jets. Or a man who obsessively fears contamination may yield to that fear by performing cleaning rituals.The study also found that compulsions sometimes serve to help control obsessions. A teenager describes how she tried to control her obsessive fears of contamination by performing counting and verbal rituals: Patient: If I heard the word, like, something that had to do with germs or disease, it would be considered something bad, and so I had things that would go through my mind that were sort of like “cross that out and it’ll make it okay” to hear that word. Interviewer: What sort of things? Patient: Like numbers or words that seemed to be sort of like a protector.

Interviewer: What numbers and what words were they?Patient It started out to be the number 3 and multiples of 3 and then words like “soap and water,” something like that; and then the multiples of 3 got really high, and they’d end up to be 124 or something like that. It got real bad then. (Spitzer et al. , 1981,p.

137) Many people with obsessive-compulsive disorder worry that they will act out their obsessions. A man with obsessive images of wounded loved ones may worry that he is but a step away from committing murder; or a woman with obsessive urges to yell out in church may worry that she will one day give in to them and embarrass herself.Most such concerns are unfounded. Although many obsessions lead to compulsive acts-particularly to cleaning and checking compulsions-they do not usually lead to violence or immoral conduct. Obsessive-compulsive disorder was once among the least understood of the psychological disorders. In recent decades, however, researchers have begun to learn more about it.

The most influential explanations and treatments come from the psychodynamic, behavioral, cognitive, and biological models. THE PSYCHODYNAMIC PERSPECTIVEPsychodynamic theorists believe that an anxiety disorder develops when children come to fear their own id impulses and use ego defense mechanisms to lessen the resulting anxiety. What distinguishes obsessive-compulsive disorder from other anxiety disorders, in their view, is that here the battle between anxiety-provoking id impulses and anxiety-reducing defense mechanisms is not buried in the unconscious but is played out in dramatic thoughts and actions. The id impulses usually take the form of obsessive thoughts, and the ego defenses appear as counter thoughts or compulsive actions.A woman who keeps imagining her mother lying broken and bleeding, for example, may counter those thoughts with repeated safety checks throughout the house. According to psychodynamic theorists, three ego defense mechanisms are particularly common in obsessive-compulsive disorder: isolation, undoing, and reaction formation. People who resort to isolation simply disown their unwanted thoughts and experience them as foreign intrusions.

People who engage in undoing perform acts that are meant to cancel out their undesirable impulses.Those who wash their hands repeatedly, for example, may be symbolically undoing their unacceptable id impulses. People who develop a reaction formation take on a lifestyle that directly opposes their unacceptable impulses. A person may live a life of compulsive kindness and devotion to others in order to counter unacceptably aggressive impulses. Sigmund Freud traced obsessive-compulsive disorder to the anal stage of development (occurring at about 2 years of age). He proposed that during this stage some children experience intense rage and shame as a result of negative toilet-training experiences.Other psychodynamic theorists have argued instead that such early rage reactions are rooted in feelings of insecurity (Erikson, 1963; Sullivan, 1953; Horney, 1937). Either way, these children repeatedly feel the need to express their strong aggressive id impulses while at the same time knowing they should try to restrain and control the impulses.

If this conflict between the id and ego continues, it may eventually blossom into obsessive-compulsive disorder. Overall, research has not clearly supported the psychodynamic explanation (Fitz, 1990).When treating patients with obsessive-compulsive disorder, psychodynamic therapists try to help the individuals uncover and overcome their underlying conflicts and defenses, using the customary techniques of free association and therapist interpretation. Research has offered little evidence, however, that a traditional psychodynamic approach is of much help (Bram & Bjorgvinsson, 2004; Foa & Franklin, 2004). Thus some psychodynamic therapists now prefer to treat these patients with short-term psychodynamic therapies, which are more direct and action-oriented than the classical techniques.

THE BEHAVIORAL PERSPECTIVEBehaviorists have concentrated on explaining and treating compulsions rather than obsessions. They propose that people happen upon their compulsions quite randomly. In a fearful situation, they happen just coincidentally to wash their hands, say, or dress a certain way.

When the threat lifts, they link the improvement to that particular action. After repeated accidental associations, they believe that the action is bringing them good luck or actually changing the situation, and so they perform the same actions again and again in similar situations. The act becomes a key method of avoiding or reducing anxiety (Frost & Steketee, 2001).

The famous clinical scientist Stanley Rachman and his associates have shown that compulsions do appear to be rewarded by a reduction in anxiety. In one of their experiments, for example, 12 research participants with compulsive hand-washing rituals were placed in contact with objects that they considered contaminated (Hodgson & Rachman, 1972) . As behaviorists would predict, the hand-washing rituals of these participants seemed to lower their anxiety. If people keep performing compulsive behaviors in order to prevent bad outcomes and ensure positive outcomes, can’t they be taught that such behaviors are not really serving this purpose?In a behavioral treatment called exposure and response prevention (or exposure and ritual prevention), first developed by psychiatrist Victor Meyer (1966), clients are repeatedly exposed to objects or situations that produce anxiety, obsessive fears, and compulsive behaviors, but they are told to resist performing the behaviors they feel so bound to perform. Because people find it very difficult to resist such behaviors, therapists may set an example first. Many behavioural therapists now use exposure and response prevention in both individual and group therapy formats.Some of them also have people carry out self help procedures at home (Foa et aI. 2005).

That is, they assign homework in exposure and response prevention, such as these assignments given to a woman with a cleaning compulsion: Do not mop the floor of your bathroom for a week. After this, clean it within three minutes, using an ordinary mop. Use this mop for other chores as well without cleaning it.

Buy a fluffy mohair sweater and wear it for a week. When taking it off at night, do not remove the bits of fluff. Do not clean your house for a week. You, your husband, and children all have to keep shoes on.Do not clean the house for a week. Drop a cookie on the contaminated floor, pick the cookie up and eat it. Leave the sheets and blankets on the floor and then put them on the beds.

Do not change these for a week. (Emmelkamp, 1982,pp. 299-300) Eventually this woman was able to set up a reasonable routine for cleaning herself and her home. Between 55 and 85 percent of clients with obsessive-compulsive disorder have been found to improve considerably with exposure and response prevention, improvements that often continue indefinitely (Abramowitz et aI. 2008; Hollon et aI.

2006; Franklin, Riggs, ; Pai, 2005).The effectiveness of this approach suggests that people with obsessive-compulsive disorder are like the superstitious man in the old joke who keeps snapping his fingers to keep elephants away. When someone points out, “But there aren’t any elephants around here;’ the man replies, “See? It works! ” One review concludes, “With hindsight, it is possible to see that the obsessional individual has been snapping his fingers, and unless he stops (response prevention) and takes a look around at the same time (exposure), he isn’t going to learn much of value about elephants” (Berk & Efran, 1983, p. 46). At the same time, research has revealed certain limitations in exposure and response prevention.

Few clients who receive the treatment overcome all their symptoms, and as many as one-quarter fail to improve at all (Foa et aI. , 2005; Frost & Steketee, 2001). In addition, many individuals drop out of or even refuse to enter into this kind of treatment because they consider it too demanding or threatening (Radomsky et al. , 2008).

And, finally, the approach is of limited help to those who have obsessions but no compulsions (Hohagen et aI. 1998). THE COGNITIVE PERSPECTIVE Cognitive theorists begin their explanation of obsessive-compulsive disorder by pointing out that everyone has repetitive, unwanted, and intrusive thoughts. Anyone might have thoughts of harming others or being contaminated by germs, for example, but most people dismiss or ignore them with ease (Baer, 2001). Those who develop this disorder, however, typically blame themselves for such thoughts and expect that somehow terrible things will happen (Shafran, 2005; Salkovskis, 1999, 1985).

To avoid such negative outcomes, they try to neutralize the thoughts-thinking or behaving in ways meant to put matters right or to make amends (Salkovskis et aI. 2003). Neutralizing acts might include requesting special reassurance from others, deliberately thinking “good” thoughts, washing one’s hands, or checking for possible sources of danger. When a neutralizing effort brings about a temporary reduction in discomfort, it is reinforced and will likely be repeated.

Eventually the neutralizing thought or act is used so often that it becomes, by definition, an obsession or compulsion.At the same time, the individual becomes more and more convinced that his or her unpleasant intrusive thoughts are dangerous. As the person’s fear of such thoughts increases, the thoughts begin to occur more frequently and they, too, become obsessions. In support of this explanation, studies have found that people who have obsessive compulsive disorder experience intrusive thoughts more often than other people, resort to more elaborate neutralizing strategies, and experience reductions in anxiety after using neutralizing techniques (Shafran, 2005; Salkovskis et aI. 2003). Although everyone sometimes has undesired thoughts, only some people develop obsessive-compulsive disorder. Why do these individuals find such normal thoughts so disturbing to begin with? Researchers have found that this population tends (1) to be more depressed than other people (Hong et aI.

, 2004), (2) to have exceptionally high standards of conduct and morality (Rachman, 1993), (3) to believe that their intrusive negative thoughts are equivalent to actions and capable of causing harm to themselves or others (Steketee et al. 003), and (4) generally to believe that they should have perfect control over all of their thoughts and behaviors (Coles et aI. , 2005; Frost & Steketee, 2002,2001). Cognitive therapists focus treatment on the cognitive processes that help produce and maintain obsessive thoughts and compulsive acts. Initially, they provide psychoeducation, teaching clients about their misinterpretations of unwanted thoughts, excessive sense of responsibility, and neutralizing acts.

They then move on to help the clients identify, challenge, and change their distorted cognitions.Many cognitive therapists also include habituation training in their sessions, directing clients to call forth their obsessive thoughts again and again. The clinicians expect that with such repetitions, the obsessive thoughts will lose their power to frighten or threaten the clients, and thus will produce less anxiety and trigger fewer new obsessive thoughts and compulsive acts (Franklin et aI. , 2002; Salkovskis & Westbrook, 1989). It appears that such cognitive techniques often help reduce the number and impact of obsessions and compulsions (Rufer et al. , 2005; Eddy et aI 2004).

While the behavioral approach (exposure and response prevention) and the cognitive approach have each been of help to clients with obsessive-compulsive disorder, some research suggests that a combination of the two approaches is often more effective than either intervention alone (Foa et aI. , 2005; Franklin et aI. , 2005; Clark, 2004). In cognitive-behavioral treatments of this kind, clients are taught to view their obsessive thoughts as inaccurate occurrences rather than as valid and dangerous cognitions for which they are responsible and upon which they must act.As they become better able to identify and understand such thoughts-to recognize them for what they are-they also become less inclined to act on them, more willing and able to subject themselves to the rigors of exposure and response prevention, and more likely to make gains in that behavioral technique.

THE BIOLOGICAL PERSPECTIVE Family pedigree studies provided the earliest hints that obsessive-compulsive disorder may be linked in part to biological factors (Lambert & Kinsley, 2005).Studies of twins found that if one identical twin manifests obsessive-compulsive disorder, the other twin also develops it in at least 53 percent of cases. In contrast, among fraternal twins (twins who share half rather than all their genes) both twins manifest the disorder in only 23 percent of cases. In short, the more similar the gene composition of two individuals, the more likely both are to experience obsessive-compulsive disorder, if indeed one of them manifests the disorder.Currently, more direct genetic studies are being conducted to try to pinpoint the gene or combination of genes that may predispose some individuals to develop this disorder (Miguel et aI. , 2005, 1997; Delorme et aI. , 2004).

In recent years two lines of research have uncovered evidence that biological factors play a key role in obsessive-compulsive disorder, and promising biological treatments for the disorder have been developed as well. The research points to (1) abnormally low activity of the neurotransmitter serotonin and (2) abnormal functioning in key regions of the brain. . Abnormal Serotonin Activity Serotonin, like GABA and norepinephrine, is a brain chemical that carries messages from neuron to neuron.

The first clue to its role in obsessive-compulsive disorder was, once again, a surprising finding by clinical researchers-this time that two antidepressant drugs, clomipramine and fluoxetine (Anafranil and Prozac), reduce obsessive and compulsive symptoms (Stein & Fineberg, 2007). Since these particular drugs also increase serotonin activity, some researchers concluded that the disorder is caused by low serotonin activity.In fact, only those antidepressant drugs that increase serotonin activity help in cases of obsessive-compulsive disorder; antidepressants that mainly affect other neurotransmitters typically have no effect on it (Jenike, 1992). Although serotonin is the neurotransmitter most often cited in explanations of obsessive-compulsive disorder, recent studies have suggested that other neurotransmitters, particularly glutamate, CABA, and dopamine, may also play important roles in the development of this disorder (Lambert & Kinsley, 2005).Some researchers even argue that, with regard to obsessive-compulsive disorder, serotonin may act largely as a neuromodulator, a chemical whose primary function is to increase or decrease the activity of other key neurotransmitters. 2. Abnormal Brain Structure and Functioning Another line of research has linked obsessive-compulsive disorder to abnormal functioning by specific regions of the brain, particularly the orbitofrontal cortex (just above each eye) and the caudate nuclei (structures located within the brain region known as the basal ganglia).

These regions are part of a brain circuit that converts sensory information into thoughts and actions (Stein & Fineberg, 2007; Chamberlain et al. , 2005; Szeszko et al. , 2005). The circuit begins in the orbitofrontal cortex, where sexual, violent, and other primitive impulses normally arise. These impulses next move on to the caudate nuclei, which act as filters that send only the most powerful impulses on to the thalamus, the next stop on the circuit.

If impulses reach the thalamus, the person is driven to think further about them and perhaps to act.Many theorists now believe that either the orbitofrontal cortex or the caudate nuclei of some people are too active, leading to a constant eruption of troublesome thoughts and actions (Lambert & Kinsley, 2005). Additional parts of this brain circuit have also been identified in recent years, including the cingulate cortex and, once again, the amygdala (Stein & Fineberg, 2007). Of course, it may turn out that these regions also play key roles in obsessive-compulsive disorder.In support of this brain circuit explanation, medical scientists have observed for years that obsessive-compulsive symptoms do sometimes arise or subside after the orbitofrontal cortex, caudate nuclei, or other regions in the circuit are damaged by accident or illness (Coetzer, 2004; Berthier et al. , 2001). In one highly publicized case, a patient with obsessive-compulsive disorder tried to commit suicide by shooting himself in the head.

Although he survived the shot, he did considerable damage to the brain areas in question.Perhaps as a result of the injury, his obsessive and compulsive symptoms declined dramatically. Similarly, neuroimaging studies, which offer pictures of brain functioning and structure, have shown that the caudate nuclei and the orbitofrontal cortex of research participants with obsessive-compulsive disorder are more active than those of control participants (Chamberlain et al. , 2005; Baxter et al. , 2001, 1990).

The serotonin and brain circuit explanations may themselves be linked.It turns out that serotonin-along with the neurotransmitters glutamate, GABA, and dopamine plays a key role in the operation of the orbitofrontal cortex, caudate nuclei, and other parts of the brain circuit; certainly abnormal activity by one or more of these neurotransmitters could be contributing to the improper functioning of the circuit. 3.

Biological Therapies Ever since researchers first discovered that certain antidepressant drugs help to reduce obsessions and compulsions, these drugs have been used to treat obsessive-compulsive disorder (Julien, 2008).We now know that the drugs not only increase brain serotonin activity but also help produce more normal activity in the orbitofrontal cortex and caudate nuclei (Stein & Fineberg, 2007; Baxter et aI. , 2000, 1992).

Studies have found that clomipramine (Anafranil), fluoxetine (Prozac), fluvoxamine (Luvox), and similar antidepressant drugs bring improvement to between 50 and 80 percent of those with obsessive-compulsive disorder (Bareggi et aI. , 2004). The obsessions and compulsions do not usually disappear totally, but on average they are cut almost in half within eight weeks of treatment (DeVeaugh-Geiss et al. 1992).

People who are treated with such drugs alone, however, tend to relapse if the medication is stopped. Thus, more and more individuals with obsessive-compulsive disorder are now being treated by a combination of behavioral, cognitive, and drug therapies. According to research, such combinations often yield higher levels of symptom reduction and bring relief to more clients than do each of the approaches alone-improvements that often last for years (Kordon et al. 2005; Rufer et al. , 2005).

Obviously, the treatment picture for obsessive-compulsive disorder, like that for panic disorder, has improved greatly over the past 15 years. Once a very stubborn problem, this disorder is now helped by several forms of treatment, often used in combination. In fact, at least two studies suggest that the behavioral, cognitive, and biological approaches may ultimately have the same effect on the brain. In these investigations, both participants who esponded to cognitive-behavioral treatments and those who responded to antidepressant drugs showed marked reductions in activity in the caudate nuclei (Stein & Fineberg, 2007; Schwartz & Begley, 2002; Baxter et aI. , 2000, 1992). DIAGNOSIS AND PHENOMENOLOGY OF OCD Obsessive-compulsive disorder (OCD) is one of the most severe and chronic of the anxiety disorders delineated in the current psychiatric nomenclature (American Psychiatric Association [APA], 1994). It is characterized by the presence of obsessions or compulsions, although the majority of patients report both types of symptoms (Foa & Kozak, 1995).An obsession is any recurrent, intrusive thought, image, or urge that is unwanted but cannot be controlled.

Obsessions differ from the excessive preoccupation with real-life worries that characterizes generalized anxiety disorder (GAD) in content, form, resistance, and precipitating stimuli (Turner, Beidel, & Stanley, 1992). Patients with the two disorders are also easily distinguishable based on core clinical features (Brown, Moras, Zinbarg, & Barlow, 1993). The most common types of obsessions involve themes of contamination, dirt or illness (e. g. fearing that one will contract or transmit a specific disease, such as cancer or HIV, or a more general, vague fear of not being clean enough), and pathological doubting (e. g. , that some action has not been performed adequately and will consequently result in harm to self and/or others) (Rasmussen & Eisen, 1994). Other common themes include the need for symmetry or orderliness, somatic concerns, and aggressive, sexual, or religious ideation.

Generally, patients try to suppress or ignore the thoughts, and diagnostic criteria require that patients realize that the obsessions are products of their own minds (APA, 1994).A compulsion is any purposeful, repetitive behaviour or mental activity that is performed in a ritualistic or stereotypical way, generally with the goal of reducing anxiety associated with obsessive ideation. As such, compulsions can be conceptualized as escape or avoidance mechanisms, although it should be noted that not all conceptualizations of the disorder include a central role for anxiety (Antony, Downie, & Swinson, 1998). The most frequently reported compulsive behaviours include repetitive washing (e. g. handwashing, showering, house cleaning) and checking (e. g.

, of locks, appliances, numerical figures, or mathematical calculations) (Rasmussen & Eisen, 1994). These classes of behaviors generally are associated, respectively, with obsessive thoughts of contamination and excessive doubting (Baer, 1994; Rachman & Hodgson, 1980). Other common types of compulsions include repeating rituals (e.

g. , getting up and down from a chair repeatedly, going in and out of doorways), ordering/arranging behaviors, and hoarding. Cognitive compulsions (e.

g. mental counting or repetition of certain words, phrases, or images) also occur frequently and generally serve the same function as behavioral rituals (Foa & Kozak, 1995). However, mental rituals often go unnoticed by inexperienced clinicians. To differentiate obsessions from cognitive compulsions, it is essential to determine the function of the mental activity. If the function is to reduce discomfort about an obsessive thought, characterization of the cognition as a compulsion should be considered. DSM-IV-TR criteria: A.

Either obsessions or compulsions: Obsessions as defined by (1), (2), (3), and (4): 1) recurrent and persistent thoughts, impulses, or images that are experienced at some time during the disturbance, as intrusive and inappropriate and that cause marked anxiety or distress (2) the thoughts, impulses, or images are not simply excessive worries about real-life problems (3) the person attempts to ignore or suppress such thoughts, impulses, or images, or to neutralize them with some other thought or action (4) the person recognizes that the obsessional thoughts, impulses, or images are a product of his or her own mind (not imposed from without as in thought insertion) Compulsions as defined by (1) and (2): 1) repetitive behaviors (e. g. , hand washing, ordering, checking) or mental acts (e. g.

, praying, counting, repeating words silently) that the person feels driven to perform in response to an obsession, or according to rules that must be applied rigidly (2) the behaviors or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these behaviors or mental acts either are not connected in a realistic way with what they are designed to neutralize or prevent or are clearly excessive B.At some point during the course of the disorder, the person has recognized that the obsessions or compulsions are excessive or unreasonable. Note: This does not apply to children. C.

The obsessions or compulsions cause marked distress, are time consuming (take more than 1 hour a day), or significantly interfere with the person’s normal routine, occupational (or academic) functioning, or usual social activities or relationships. D. I another Axis I disorder is present, the content of the obsessions or compulsions is not restricted to it (e.

. , preoccupation with food in the presence of an Eating Disorder; hair pulling in the presence of Trichotillomania; concern with appearance in the presence of Body Dysmorphic Disorder; preoccupation with drugs in the presence of a Substance Use Disorder; preoccupation with having a serious illness in the presence of Hypochondriasis; preoccupation with sexual urges or fantasies in the presence of a Paraphilia; or guilty ruminations in the presence of Major Depressive Disorder). E.The disturbance is not due to the direct physiological effects of a substance (e.

g. , a drug of abuse, a medication) or a general medical condition. To diagnose OCD, patients must acknowledge at some point that the symptoms are/were excessive and unreasonable. However, diagnostic criteria call for specification of poor insight when the patient fails to recognize the irrationality of the thoughts or behaviors at the time of diagnosis (APA, 1994). Patients in this subgroup also are often classified as exhibiting overvalued ideation (OVI).Although early clinical data indicated that OVI was associated with poor response to behavioural treatment (Foa, 1979), more recent studies addressing this issue have not been consistent (Kozak & Foa, 1994). This literature is difficult to interpret, however, given that patients with OCD exhibit a wide range of insight and fixity of beliefs (Eisen & Rasmussen, 1993; Foa & Kozak, 1995) that make categorization into OVI and non-OVI subgroups challenging at best.

Moreover, until recently, no psychometrically sound measure of OVI was available.Due to the lack of well standardized assessment tools, it has been difficult to interpret and integrate findings across studies. However, preliminary data on a new measure created by Eisen and colleagues show promise in this regard (Eisen et al. , 1998). The Brown Assessment of Beliefs Scale is a seven-item clinician-rated scale that assesses degree of delusionality in OCD and other psychiatric disorders. Initial psychometric data suggested strong inter rater agreement, internal consistency, convergent and divergent validity, and sensitivity to change (Eisen et al. , 1998).

As such, this measure should provide a solid tool for further investigation into the role of overvalued ideation in OCD. As with other psychiatric disorders, to diagnose OCD, the symptoms need to create significant distress and/or interfere with functioning. Numerous studies have documented that patients with OCD experience significant disruption in social and family relationships, impaired work performance, and decreased quality of life (Antony, Roth, Swinson, Huta, & Devins, 1998; Calvocoressi et al. , 1995; Hollander et al.

, 1997; Koran, Thienemann, & Davenport, 1996).Economic costs of the disorder are also high due to inappropriate treatments, unemployment, absenteeism from work, and increased use of welfare or family support (Hollander et al. , 1997; Steketee, Grayson, & Foa, 1987).

In these instances, OCD should be considered a severe psychiatric disorder that has pervasive and serious impact on the individual and society. SYMPTOM SUBTYPES Given the wide variety of symptom patterns that may be present in OCD, a number of attempts have been made to sub classify the disorder to enhance understanding of its pathophysiology and treatment.Most often, attempts to identify subtypes have been based on the predominant type of rituals reported by the patient. In these schemes, subgroups of patients always include (but are not limited to) those with predominant washing and checking rituals. These types of rituals are the most commonly reported by clinic patients (Rasmussen & Eisen, 1994).

As such, it is not surprising that much of the evidence that supports the utility of behavioral treatment for OCD has been obtained largely with patients who can be classified as ‘‘washers’’ or ‘‘checkers’’ (Ball, Baer, & Otto, 1996).Studies of the potential utility of sub classifying OCD in this manner have indicated a variety of differences in demographic and clinical variables for patients classified as ‘‘washers’’ and ‘‘checkers. ’’ For example, patients in these two subgroups differ in age of onset and gender distribution (Khanna & Mukherjee, 1992; Minichiello, Baer, Jenike, & Holland, 1990), frequency of personality disorders (Horesh, Dolberg, Kirschenbaum-Aviner, & Kotler, 1997), triggers for obsessional fears, and retrospective reports of parental style (Steketee, Grayson, & Foa, 1985).These data suggest the potential utility of a symptom classification scheme to enhance understanding and treatment of OCD. Recent factor analyses of OCD symptoms in larger groups of patients suggested three or four major subgroups of symptoms.

Baer (1994) reported an analysis of symptoms in 107 patients that yielded three factors characterized by symmetry/hoarding (symmetry and saving obsessions, and ordering, hoarding, repeating, and counting rituals), contamination/cleaning, and pure obsessions (aggressive, sexual, and religious obsessions).Leckman and colleagues (Leckman et al. , 1997) reported four factors in two independent samples of more than 300 patients with OCD. These factors included obsessions/checking (aggressive, sexual, religious, and somatic obsessions and checking rituals), symmetry/ordering (including also repeating and counting compulsions), cleanliness/washing, and hoarding. Overlap in the factor structures of these two reports is evident, although no data yet have addressed the utility of sub classifying patients according to these broader subgroups of symptoms.In fact, despite evidence of meaningful differences between washers and checkers, the general utility of classifying patients according to symptom subtypes has been questioned, given that symptom clusters generally are not mutually exclusive and constellations of symptoms may change over time (Baer, 1994; Rettew, Swedo, Leonard, Lenane, & Rapoport, 1992).

Other sub classification schemes have also been suggested, the most viable of them probably is based on coexistent diagnoses.In particular, coexistent Tourette’s syndrome or chronic tic disorder in OCD has been associated with differential obsessive-compulsive symptom profiles (Baer, 1994; Leckman et al. , 1997), gender distribution (George et al. , 1993; Zohar et al. , 1997), age of onset for OCD and neurochemical findings (Leonard et al. , 1992), and treatment response (McDougle, Goodman, Leckman, Barr, Heninger, & Price, 1993).

this literature taken together supports the potential utility of sub classifying patients with OCD who also have a chronic tic disorder to enhance clinical understanding and treatment of patients.Similarly, patients with some coexistent personality disorders or features have unique patterns of OCD symptoms (Baer, 1994; Stanley, Turner, & Borden, 1990) and differential treatment response (McDougle, Goodman, Leckman, Lee, Heninger, & Price, 1994). This literature is less well developed, however, and requires further study. Possibly of even more heuristic value are sub classification schemes, based on function rather than content of symptoms. Such systems allow sub classification of patients regardless of specific symptom constellations that may vary over time.Mavissakalian (1979) proposed such a system that included four forms of obsessive-compulsive symptoms: (1) obsessions only, (2) obsessions plus anxiety-reducing compulsions, (3) obsessions plus anxiety-increasing compulsions, and (4) compulsions independent of anxiety and/or obsessions.

Although this type of system holds some promise for treatment refinement (Mavissakalian, 1979), very little relevant empirical work has addressed the utility of functional classification schemes.In the context of a DSM-IV field trial, Foa and Kozak (1995) examined the usefulness of subcategories of OCD including predominantly obsessions, predominantly compulsions, and mixed obsessions and compulsions. Results revealed that more than 90% of patients reported both obsessive and compulsive symptoms, although based on interview data; clinicians categorized 30% of patients with predominantly obsessions, 21% with predominantly compulsions, and 49% with mixed obsessions and compulsions.Significant differences in the frequency of various specific symptoms occurred across these subgroups, although data overall were equivocal with regard to the utility of this type of classification. In summary, numerous models have been proposed for sub classifying OCD. To date, the most promising of these involve subgroups based on the presence or absence of co-occurring chronic tic disorders and the predominant type of symptom reported; the majority of data here address differences between patients with primary washing or checking compulsions.COMORBIDITY, DIFFERENTIAL DIAGNOSIS, AND THE OBSESSIVE-COMPULSIVE SPECTRUM DISORDERS OCD is frequently accompanied by increased levels of anxiety and depression; estimates of coexistent disorders range from 42–83% (Antony et al. , 1998).

Despite these high rates of overlap with other disorders, the diagnosis of OCD can be made quite reliably, particularly when behavioral compulsions are present (Brown, 1998). Key differential diagnostic issues still are relevant, however.Generally, the differentiation of OCD from other anxiety disorders is fairly straightforward. First, although there is clearly overlap between obsessional thinking and worry, the diagnostic differentiation of OCD and GAD can be made reliably (Brown et al. , 1993).

In differentiating these disorders, it is of note that obsessions generally are associated with a greater degree of resistance and increased perceptions of unacceptability than worry (Turner et al. , 1992).Obsessions are also less likely to be precipitated by and focused on circumstances of daily living (Turner et al. , 1992). Even when GAD is diagnosed in patients with principal OCD, it is associated with more frequent worries about daily life events (Abramowitz & Foa, 1998). Moreover, although repetitive checking may be present in GAD, rituals that accompany OCD are usually more pervasive and intrusive. Differentiation of OCD and other disorders with more focal fears (e.

g. specific phobia, social phobia, specific subtype) is usually not difficult because any obsessional ideation that accompanies these syndromes revolves around a single fear. Ritualistic behavior also typically does not accompany fears with a more specific focus.

The distinction between OCD and specific phobias of illness, however, can be slightly more complicated because fears of contamination/illness are the most prevalent form of obsessions generally reported (Brown, 1998).In these cases, differentiation can be relatively straightforward if rituals accompany the fear. In addition, specific phobias of illness involve more focused health-related fears than the pervasive concerns usually evident in OCD. Differentiating OCD and depression is also an important issue, given the high rates of comorbidity between these conditions.

Although figures vary across studies, as many as one-third of patients with OCD also meet criteria for coexistent depression or dysthymia (Antony et al. , 1998a).In these cases, it can be important for treatment planning to identify which disorder is considered principal. Generally, the principal disorder is assumed to be that with the earlier onset (Turner & Beidel, 1988). Using this criterion, OCD more often is considered the principal diagnosis when both disorders are present (Antony et al. , 1998a).

There is support, however, for the notion that all anxiety and affective disorders share a similar biological pathophysiology, although environmental factors shape symptom expression Kendler, Heath, Martin, & Eaves, 1987). Of more recent interest in the literature, however, are issues concerning the relationship between OCD and a wide range of other psychiatric and neuropsychiatric disorders that, it is hypothesized, comprise a group of disorders known as the obsessive-compulsive spectrum disorders (Hollander, 1993; McElroy, Phillips, & Keck, 1994). Disorders proposed as members of this spectrum include the somatoform disorders (e. g. , body dysmorphic disorder, hypochondriasis), eating disorders (e. g. anorexia nervosa, bulimia nervosa, and binge-eating disorder), impulse control disorders (e. g.

, trichotillomania, pathological gambling) and related symptoms (skin picking, nail biting, and compulsive buying), and movement disorders (e. g. , Tourette’s disorder, Sydenham’s chorea). These disorders, it has been hypothesized, share common phenomenological features, patterns of comorbidity, family history, clinical course, treatment response, and neurobiological mechanism with OCD. The proposed concept of obsessive-compulsive spectrum disorders has generated much controversy in the field.

In particular, some authors have argued that this classification scheme is vague, over inclusive, and characterized by a lack of clear inclusion and exclusion criteria (Rasmussen, 1994). Other authors have argued that the spectrum disorders are part of an even broader class of affective disorders (McElroy, Hudson, & Pope, 1992). Sub classification schemes have also been proposed, and some include disorders of altered risk assessment, incompleteness/habit spectrum disorders, and psychotic spectrum disorders (Pigott, L’Heureux, Dubbert, Bernstein, & Murphy, 1994).

Another perspective suggests that disorders along the obsessive-compulsive spectrum vary across a continuum of compulsivity versus impulsivity (Hollander & Cohen, 1996). In this scheme, compulsive disorders, it is proposed, reflect excessive harm avoidance and risk aversion, whereas impulsive disorders are characterized by minimization of harm and risk. Empirical literature addressing the potential overlap between OCD and the other proposed spectrum disorders is limited at present. Nevertheless, in some cases, the apparent overlap is more striking than in others.

It has been suggested that those disorders that would be classified along the compulsive end of the spectrum (e. g. , the somatoform and eating disorders) are more similar to OCD than those proposed that fall along the impulsive end (e. g. , impulse control disorders) (Goldsmith, Shapira, Phillips, & McElroy, 1998).

The extant literature supports this notion, at least in part because of striking phenomenological similarities between OCD and body dysmorphic disorder (BDD), hypochondriasis, and eating disorders.In particular, preoccupations with perceived physical defects, serious disease, and food or body weight that are present in BDD, hypochondriasis, and eating disorders, respectively, strongly resemble the obsessions that occur in OCD. In addition, ritualistic behavior generally accompanies these other syndromes.

For example, patients with BDD frequently check their appearance in the mirror, seek reassurance about the imagined physical defect, and perform excessive grooming behaviors.Patients with hypochondriasis often repetitively check physical symptoms, request medical treatment, and seek reassurance regarding health. Individuals with eating disorders also regularly report repetitive behaviors surrounding eating behaviors. In addition to these striking phenomenological similarities, there is some evidence that these disorders respond to pharmacological interventions (e. g.

, serotonergic reuptake inhibitors) and behavioral treatments (exposure and response prevention) that are the treatments of choice for OCD (Goldsmith et al. , 1998).Despite these areas of overlap between OCD and those spectrum disorders proposed, potentially important differences in these conditions are also evident. For example, both BDD and hypochondriasis generally are associated with greater levels of impaired insight than is typically seen in OCD. Additionally, bulimia nervosa and binge eating disorder are associated with more frequent impulsive behaviors than OCD.

Finally, there is some evidence that hypochondrias and eating disorders also respond to nonserotonergic antidepressants that have not demonstrated efficacy in OCD (Goldsmith et al. , 1998).Nevertheless, the possibility that these disorders are related in some way to OCD deserves additional empirical attention. In the case of those disorders proposed that lie along the impulsive end of the spectrum, it is our opinion that differences among these disorders in phenomenology, neurobiology, and treatment far outweigh any similarities.

The impulse control disorders (ICDs; e. g. , pathological gambling, kleptomania, trichotillomania) and possible ICDs (e. g.

, nail biting, repetitive self-mutilation, skin picking) are characterized by repetitive behaviours over which patients report no ontrol. These behaviours often, it is reported, have an anxiety relieving function, and it is in these domains that there is some overlap with OCD. Other data also have suggested overlap between the ICDs and OCD in family history and treatment response (Goldsmith et al. , 1998). Despite these areas of overlap, other phenomenological, neurobiological, and treatment data suggest important differences between OCD and ICDs. The majority of literature in this area has addressed the potential overlap between OCD and trichotillomania (TM), a disorder characterized by repetitive hair pulling.In a review of this literature, Stanley and Cohen (1999) summarized areas of similarity and dissimilarity between these conditions.

One major phenomenological difference included the fact that obsessional thoughts usually do not accompany repetitive hair pulling, although this type of cognitive activity is central to the diagnosis of OCD. In addition, hair pulling occurs in response not just to anxiety, but also to a variety of affective states, and the behavior frequently produces feelings of pleasure that are not characteristic of OCD. Moreover, sensory stimuli (e. . , itching, burning) are important precipitators of hair pulling, although these have no central role in OCD. Neurobiological and neuropsychological correlates of OCD and TM are also different, although the literature addressing these issues in TM is still somewhat limited.

Finally, pharmacological treatment data for TM do not provide a consistent picture of the efficacy of serotonergic reuptake inhibitors, and the modes of behavioural treatment for TM (habit reversal training) and OCD (exposure and response prevention) are quite different.In summary, the range of important differences between these two syndromes calls into question the utility of combining them under a single spectrum of obsessive-compulsive related disorders. However, Stanley and Cohen (1999) highlighted the notion that some subtypes of TM may reflect more overlap with OCD and further suggested that any appearance of association between these disorders may result from the heightened states of negative affect that accompany each. These hypotheses require further study.

Overall, the notion of an obsessive-compulsive spectrum of disorders continues to generate controversy in the field.Difficulties in assessing the utility of this scheme reflect in part the fact that there are not yet any established criteria for membership in this family of disorders. Furthermore, the amount of literature that has provided direct comparisons between patients with OCD and those with proposed related disorders remains limited.

EPIDEMIOLOGY The now well-known Epidemiological Catchment Area (ECA) survey conducted during the early 1980s indicated lifetime prevalence rates for OCD of 1. 9 to 3. 3% in five U. S. communities and an overall rate of 2. 5% (Karno, Golding, Sorenson, & Burnam, 1988).These rates were much higher than any previous estimates and were confirmed by similar epidemiological, albeit smaller scale, surveys conducted at approximately the same time in the United States and Canada (Bland, Orn, & Newman, 1988; Henderson & Pollard, 1988).

In all of these studies, however, interviews were conducted by lay interviewers, and it is notable that prevalence estimates were considerably lower in surveys using clinician interviewers (Faravelli, Degl’Innocenti, & Giardinelli, 1989; Nestadt, Samuels, Romanoski, Folstein, & McHugh, 1994).In fact, a more recent study confirmed that prevalence rates for OCD within a single sample were indeed lower when clinicians, rather than lay interviewers, conducted diagnostic interviews (Stein, Forde, Anderson, & Walker, 1997). Issues such as lay interviewers’ inexperience in establishing and labeling psychiatric symptoms and difficulty in estimating degree of dysfunction and distress are particularly relevant in this regard (Stein et al. , 1997). The limitations of the ECA study are well known and have been discussed in detail elsewhere (Beidel & Turner, 1991; McNally, 1994).The most striking of these, however, are the aforementioned potential for over diagnosis due to use of lay interviewers and diagnostic structured interview tools that do not allow for follow-up questions to clarify patient reports. Of even more concern are recent data suggesting poor temporal stability of OCD diagnoses for a subset of ECA survey participants who were reassessed 12 months after the initial interview (Nelson & Rice, 1997).

Taken together, these data call into question prevalence rates based on the ECA survey.It is unfortunate that the only subsequent large epidemiological survey conducted in the United States, the National Comorbidity Survey, failed to assess the prevalence of OCD (Kessler et al. , 1994).

As a result, the true prevalence of this disorder is now uncertain. At least partly due to general difficulties in estimating prevalence rates, data are mixed with regard to the impact of ethnicity on the prevalence of OCD. Across all five ECA sites, figures indicated that lifetime OCD was significantly less prevalent among Black respondents than non- Hispanic White respondents (Karno et al. 1988).

Data from the Los Angeles site alone indicated no difference in prevalence rates for OCD among Mexican-Americans and non-Hispanic Whites (Karno et al. , 1989). When ECA data were compared with surveys that used similar methodology in Canada, Puerto Rico, Germany, Taiwan, Korea, Hong Kong, and New Zealand, relatively consistent prevalence figures emerged (1. 9–2. 5%), except Taiwan where the prevalence of OCD was only 0. 7% (Weissman et al. , 1994).

In a more recent survey of more than 800 residents of Baltimore, OCD tended to be more prevalent among Whites (2. 1%) than non-Whites (0. %) (Nestadt et al. , 1994).

Clinical data also routinely show a greater prevalence of OCD among Whites than non-Whites (e. g. , Antony et al. , 1998a).

It is not clear, however, that interview questions are always sensitive to ethnic differences in the experience or description of relevant symptoms. It is known, for example, that members of various minority groups tend to focus on somatic complaints in descriptions of anxiety-related symptoms and often present for assistance to medical rather than psychiatric clinics (Friedman, Hatch, Paradis, Popkin, & Shalita, 1993).Other sociocultural variables, including religious background, can also significantly impact the presentation and assessment of OCD symptoms (Okasha, Saad, Khalil, Seif El Dawla, & Yehia, 1994). Thus, more research using culturally sensitive diagnostic tools is needed to ascertain the impact of ethnicity on prevalence rates of OCD. Epidemiological data generally have indicated that community prevalence rates are slightly higher for women than men (Henderson & Pollard, 1988; Karno et al. , 1988; Weissman et al.

, 1994).However, data from the ECA survey indicated that gender effects were eliminated when other demographic variables were controlled statistically (Karno et al. , 1988). Nevertheless, consistent gender differences have been demonstrated in the prevalence of specific obsessive-compulsive symptoms.

In particular, women are significantly more likely than men to report washing and cleaning rituals (Khanna & Mukherjee, 1992; Minichiello et al. , 1990), and there is some suggestion that men report more frequent sexual obsessions (Antony et al. , 1998a).These findings further support the potential role of sociocultural variables in the presentation of OCD. Gender differences have also been noted in the onset of OCD. Although the disorder most often begins between late adolescence and early adulthood, onset is earlier for males than females (Rasmussen & Eisen, 1990).

Retrospective data have suggested that later onset for women may result from the appearance of initial symptoms during pregnancy or after childbirth (Neziroglu, Anemone, & Yaryura-Tobias, 1992; Sichel, Cohen, Dimmock, & Rosenbaum, 1993).However, these findings simply may reflect the notion that OCD often has its onset after a period of significant life stress, although data addressing this issue are almost uniformly collected retrospectively and produce questionable conclusions. Although few longitudinal studies have been conducted, the course of OCD is generally chronic and unremitting without treatment. BIOLOGICAL CONTRIBUTION In 1985, Turner, Beidel, and Nathan reviewed the available data that addressed biological factors in OCD.Included in the review were genetic and family studies, neurophysiological and neuropsychological studies, neuroanatomical studies, and biochemical and pharmacological studies. Turner et al.

(1985) concluded that although biological factors correlated with OCD from the evidence available then, it did not appear that the disorder was strictly a biological abnormality. Rather, the most parsimonious explanation was that there might be a biological predisposition that leaves the individual more vulnerable to the development of OCD, perhaps from psychological and/or environmental stress.One important limitation of the studies reviewed in 1985 was that there were few data that directly assessed brain function, and inferences had to be made from indirect measures such as blood or plasma neurochemistry. During the past 15 years, advances in scientific and medical technology offer heretofore unavailable opportunities to directly assess brain structures and functions. 1. Biochemistry and Neuropharmacology Although they are an indirect assessment of brain function, data from biochemical challenge studies and pharmacological treatment outcome studies suggest that the orbital and cingulate cortex may be potential euroanatomical sites of dysfunction in OCD. Data that address the neurochemistry of OCD have been collected under three conditions: steady-state assessment in untreated patients and comparisons to normal controls, pharmacological challenge studies in untreated patients, and changes in neurochemistry after pharmacological treatment. Biochemistry: Initially, cerebral spinal fluid (CSF) studies of adult patients with OCD primarily assessed serotonin levels and activity, but the findings were inconsistent (e. g. , Thoren, Asberg, Bertilsson, Mellstrom, Sjoqvist, & Traskman, 1980; Yaryura-Tobias, Neziroglu, & Bergman, 1976).Whereas some studies found higher levels of serotonin among OCD patients, others reported reduced levels. More recently, a broader range of substances has been investigated. For example, Swedo et al. (1992) examined eight different neurochemicals and their various combinations and found only a few significant differences between patients with OCD and normal control subjects including a significant negative correlation between 5-HIAA concentration and one of eight baseline OCD severity ratings (whereas three of eight correlations were significant after 5 weeks of treatment with clomipramine).Before treatment, the concentration of arginine vasopressin (a stress responsive neurohormone) was negatively correlated with OCD symptoms, whereas corticotrophin releasing hormone (another stress-responsive neurohormone) did not differentiate the two groups. The authors concluded that arginine vasopressin might be related to OCD symptom severity whereas 5-HIAA might be associated with treatment response. However, the only comparison group used consisted of normal controls. Thus, it is unclear if the negative correlation is specific to OCD or whether it is present in other disordered mood states.Using similar methodology, Altemus et al. (1992) reported that those with OCD had significantly higher levels of arginine vasopressin and corticotropin releasing hormone compared to normal controls, similar to the findings of Swedo et al. (1992). However, in contrast to that study, Altemus et al. (1992) did not find a relationship between arginine vasopressin and any clinical rating of OCD. Corticotropin releasing factor level, on the other hand, was significantly related to scores on the Yale–Brown Obsessive-Compulsive scale but not with several other ratings of OCD.Thus, like the earlier studies that assessed serotonin, the relationship of these neurohormones to OCD is unclear. Another CSF neuropeptide, somatostatin, has also been the subject of investigation (Altemus et al. , 1993). As noted by these authors, when somatostatin is administered centrally to animals, it delays extinction of various behaviors or produces stereotyped behaviors that appear topographically similar to OCD rituals. When compared to those without a disorder, drug-free adult outpatients with OCD had higher levels of CSF somatostatin, a finding that is consist