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Obsessive compulsive disorder is a common mental illness which affects up to three percent of the population. This article provides a thorough overview of the symptoms and recognised treatment for the condition.



Obsessive compulsive disorder or OCD was until very recently considered to be a very rare disorder, but new data has revealed that it is in fact a common illness. It has been described as the "hidden epidemic" of psychology and psychiatry. It is now generally accepted that the lifetime prevalence rate of OCD is 2-3%.

Some OCD patients check and recheck that a stove is off, a door is locked, or that some disaster has not befallen their children. Some patients do not have rituals, but endure endless hours of intrusive obsessive thoughts throughout the day. The disorder may be so severe that patients are unable to work, and their families may live from crisis to crisis. If untreated, patients may be disabled for life.

Even though complete cure is rare, fortunately, there are now treatments available (behaviour therapy and psychotropic medication) that result in considerable improvement for the majority of patients. Comorbidity of OCD with depression and other anxiety disorders is common and often complicates the diagnosis. Prior to beginning treatment, it is important for the clinician to understand the entire clinical picture.

Definition of OCD:

The Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition (DSM IV) requires that a patient have either obsessions or compulsions which are a significant source of distress; are time-consuming, or significantly interfere with the person's normal routine, occupational functioning, or usual social activities or relationships with others.

At some point during the course of the illness, the patient must recognise that the obsessions or compulsions are excessive or unreasonable. This is not a necessary requirement for young children. According to DSM IV, obsessions are 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 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 or impulses or to neutralise them with some other thought or action.
  4. The person recognises that the obsessions are the product of his or her own mind, and are not imposed from without.

Clinically, the most common obsessions are repetitive thoughts of violence (e.g. harming or killing someone), contamination (e.g. becoming infected by touching something/shaking hands, and doubt such as repeatedly wondering whether one has performed some act, such as having hurt someone in a traffic accident).

Compulsions are defined by (1) and (2):

  1. Repetitive behaviours that the person feels driven to perform in response to an obsession, or according to rules that must be applied rigidly.
  2. The behaviours or mental acts are aimed at checking. This can include mental compulsions such as praying, counting and repeating words silently. Such repetitive mental actions generally serve to decrease, prevent or reduce distress or some dreaded event or situation, however, these behaviours or mental acts either are not connected in a realistic way with what they are designed to neutralise or prevent, or are clearly excessive.

Typical compulsions include handwashing, ordering and checking. Usually, obsessions are anxiety provoking while compulsions are anxiety relieving (at least over the short term).

History of understanding OCD

Centuries ago, individuals with obsessive blasphemous or sexual thoughts were considered to be possessed. This religious view of obsessions was consistent with the contemporary worldview, and the logical treatment was one designed to expel evil from the unfortunate soul who was possessed. Exorcism was the treatment of choice, with the person subjected to torture in an effort to drive the intruding entity out. Surprisingly, these treatments were apparently occasionally successful.

Obsessions and hand-washing rituals resulting from guilt were later immortalised in the 17th century by Shakespeare in the character of Lady MacBeth. With time, the explanation of the cause of obsessions and compulsions moved from a religious view to a medical one. OCD was first described in the psychiatric literature by Esquirol in 1838, and by the end of the nineteenth century, it was generally regarded as a manifestation of melancholy or depression.

By the beginning of the 20th century, theories of obsessive compulsive neurosis shifted towards psychological explanations. Janet reported successful treatment of rituals with behavioural techniques; but with Freud's writings on psychoanalysis of the Rat Man, OCD came to be from their emotional antecedents. As a result of these theories, treatment of OCD turned away from attempts to modify obsessional symptoms themselves and toward treatment of unconscious conflicts which were presumed to underline the symptoms.

With the rise of behaviour therapy in the 1950's, learning theories which had proven useful in dealing with phobic disorders were applied to OCD and although they clearly did not account for all OCD phenomenology, they led to the development of the powerful techniques of exposure and response prevention for reducing compulsive rituals.

Over the last few years research has accelerated into the biology of OCD with ongoing studies of pharmacologic agents, neurosurgical treatments, brain imaging, genetics, neuropsychological dysfunction and the association of OCD symptoms with other possibly related illnesses (see later). Theories of basal ganglia and frontal lobe dysfunction have been developed that lead to testable hypothesis concerning the underlying pathophysiology of OCD.



Even within the last decade, OCD was considered to be extremely rare (approximately 0.05% of the population). Recent studies have demonstrated a six-month prevalence of about 1.5% and a lifetime prevalence of 2-3%. This means that in the United States alone, between five and seven million people, and in NZ, 87,000 suffer from OCD. Recent pharmaceutical data indicate that far fewer than 50% of these patients are being treated.

Age of onset of OCD

The mean age of onset of OCD has been reported to be in the early 20's with over half of the patients becoming symptomatic by age 25, and three quarters by age 30. OCD usually begins in early adulthood.

In an effort to see if patients with different symptoms of OCD (e.g. washing or checking only obsessions, and mixed symptoms) had different ages of onset, research groups have found that patients with obsessions only, or only cleaning rituals had a mean age of onset around 27, while patients with only checking rituals or mixed rituals (e.g. washing and checking) had an earlier onset around age 18 to 19.


Neuro-biological theories

In rare cases, one can identify a brain insult such as encephalitis or head injury as a link to OCD, but typically there is no identifiable neurologic precipitant. With the advent of precise neuroimaging techniques such as morphometric magnetic resonance imaging (mMRI) and positron emission tomography (PET), new ways to look at the brain are now available. PET scans have indicated abnormalities in the frontal lobes, cingulum and basal ganglia of OCD patients when compared to depressed individuals and normal controls. This combination of findings from several high-technology imaging studies supports a neurologic hypothesis for OCD.

Clinically there is much overlap between patients with OCD, chronic motor tic disorder and Tourette's syndrome (TS), and a genetic relationship among these disorders seems likely (see below). Further strengthening a possible link, clinically researchers find that about 20% of OCD patients exhibit tics.

There is evidence that selective serotenergic reuptake inhibitors (SSRIs) are partially effective treatments for OCD. In the majority of drug studies to date, though there has been significant comorbidity with major depression, the depressed subjects showed no difference in treatment response of OCD symptoms.

To date, many controlled trials have demonstrated the efficacy of clomipramine. However, other selective serotenergic uptake inhibitors such as fluvoxamine (Luvox), paroxetine (Aropax), sertraline (Zoloft) and fluoxetine (Prozac) have yielded comparable beneficial results. Since differences in effectiveness among these agents are probably quite small, only large scale trials would be likely to demonstrate that any one drug is superior to another. It can be concluded that several agents that selectively block serotenergic uptake diminish OCD symptoms in children as well as adults, while pharmacologically similar agents which do not have this serotenergic selectivity are not nearly as effective.

Although the above findings suggest that alteration of brain serotenergic systems may be one mechanism through which these agents have their therapeutic effects, there remains no evidence of baseline serotenergic dysfunction in OCD patients.

It is important to keep in mind that the serotenergic system does not function in a vacuum. Neurotransmitter systems may play an equally important role in OCD. A comprehensive model of OCD must likely consider multiple transmitter systems. Findings such as the clinical ineffectiveness of the potent serotenergic agent, Zimelidine and of the anxiolytic 5-HT1A partial agonist Buspirone are difficult to explain within a strictly serotenergic model. It is possible that a balance of adrenergic and serotenergic action is necessary.

A number of studies support the hypothesis that the serotenergic system is not the only system involved in the pathophysiology of OCD. By comparing four studies of potent serotonergic agents (i.e. fluvoxamine, sertraline, fluoxetine, clomipramine) in patients with OCD it appeared that among these agents, all with selective and potent effects on serotonin reuptake, greater effect size (i.e. improvement in OC symptoms) was actually associated with less serotenergic selectivity.

Psychodynamic theories

Although psychoanalysis and psychodynamically oriented psychotherapy are not effective treatment approaches for obsessions and compulsions, theorists who write in this area have raised a number of interesting hypotheses.

Diagnosis and clinical features

Psychiatric and psychological assessment:

OCD patients usually present with specific complaints, such as pronounced obsessions or compulsive rituals, that allow the clinician to easily make the diagnosis. With non-psychiatric doctors and even with psychiatrists/psychologists that do not specialise in anxiety disorders, patients may be reluctant to discuss symptoms that they experience as terribly embarrassing or disgusting. Some patients can be in intensive psychodynamic psychotherapy or even in psychoanalysis and not even mention their OCD symptoms. For this reason, clinicians should specifically question new patients about the presence of intrusive repetitive thoughts or rituals.

Sometimes paper and pencil questionnaires allow patients to respond positively to questions that the clinician can later discuss more fully. Sometimes patients cannot resist performing rituals in front of the clinician or will resist shaking hands for fear of contamination. Most patients, however, can resist their urges when they are in public or in the doctor's office. Patients usually appear completely normal to the casual observer.

If patients divulge the nature of their obsessions, they may appear bizarre or irrational, but they almost always retain full insight and recognise that their thought and impulses are unreasonable and alien to the rest of their personality structure.

No generalisation can be made about the personality types of patients with OCD. The majority of OCD patients meet criteria for at least mild personality disorders when first presenting to a clinician, but these features usually clear as OCD symptoms improve. This suggests that conclusions cannot be drawn about personality disorder or type when the patient is actively ill with OCD or probably any severe psychiatric or medical illness.

Subtypes of OCD:

Symptoms usually can be placed into several categories: checking rituals, cleaning rituals, obsessive thoughts, obsessional slowness, or mixed rituals. Checking and cleaning rituals are the most common and multiple symptoms as a rule.

Cleaning compulsions:

A 20 year old female feared contamination for touching various things she considered dirty. She had to wear gloves or use paper towels to touch various "dirty objects." If, however, she did happen to touch her laundry, bed, door handles in public toilets, shoes, the petrol cap on her car, or other "dirty" objects, she experienced vague dirty and uncomfortable feelings, and she would engage in prolonged washing of her hands, along with any clothing that had come into contact with the object. As a result of these OCD symptoms, she was unable to work full time and her social life was almost non-existent.

Checking compulsions:

A 46 year old female checked when not sure whether she had performed an action correctly. She plugged and unplugged electric appliances many times to be sure that she actually took the plug out of the socket, and turned light switches on and off repeatedly until she was convinced that she in fact had turned them off. She stared at closed doors for up to 20 minutes to ensure that she had actually closed and locked the door. She totally avoided financial paperwork because of a compulsion to check numbers over and over again and could no longer work in her previous job as a bookkeeper. She was no longer able to read because she continually re-read sentences already read to be sure she had not missed any crucial ideas.

Primary Obsessional Disorder:

A subgroup of OC patients, perhaps as many as 15%, have only obsessive thoughts, with few or no rituals. The thoughts are typically of an aggressive, sexual, or religious nature and are upsetting and repulsive to the patient. For example, an 18 year old male could no longer go to public places because of obsessive thoughts and impulses to shout obscenities. Similarly, a 32 year old female no longer went to church, as she would experience intolerable sexual thoughts about individuals she saw in these places and even felt that she would blurt out obscenities to the priest.

Other less common subtypes:

Some patients spend inordinate periods of time placing objects in a specific order. Others suffer with primary obsessional slowness and become "stuck" for hours while performing everyday tasks such as dressing and eating. Relatively rare subtypes are being identified such as patients with obsessions and compulsions primarily aimed at controlling an overwhelming fear of having a bowel movement or being incontinent of urine in public, or young women who have extensive face picking bouts which can last for hours. Other disorders that may be closely related to OCD (sometimes called OCD spectrum disorders) are hypochondriasis (obsessive fear of illness such as AIDS, cancer or some other serious illness) and body dysmorphic disorder, Tourette's syndrome, trichotillomania, depersonalisation disorder, compulsive buying, bulimia nervosa and binge eating disorder, and anorexia nervosa.

Differential diagnosis and comorbidity

There is considerable comorbidity of other anxiety disorders and OCD; 27% of lifetime social phobia, 17% panic disorder and agoraphobia and 35% generalised anxiety disorder.

Specific phobias:

The essential feature of specific phobia is a persistent fear of a circumscribed object or situation, or of humiliation or embarrassment in certain social situations (as in social phobia/social anxiety disorder). Common specific phobias include fear of small animals (e.g. dogs, snakes and mice), insects, blood, closed spaces, heights, and air travel. In patients with OCD, phobic avoidance of certain situations that are associated with anxiety about dirt or contamination is frequent, but the concomitant presence of typical obsessions or rituals clarifies the diagnosis of OCD.


Classical compulsive rituals are not generally part of the picture of depression, but occasionally depressed patients ruminate about a particular topic and may appear to have obsessions. Careful assessment will usually reveal that the depression preceded the obsessions/ruminations. In addition, the ruminations with depression will more likely have a realistic basis. It is important to keep in mind that about a third of patients with OCD develop clinically-significant secondary depression. Fortunately, the antiobsessional drugs are also, for the most part, potent antidepressant agents as well.


In occasional OCD patients the obsessions become so severe that the patient seems truly uncertain as to whether his or her concerns are realistic or not. Such obsessions are termed overvalued ideas; for example, the patient may hold the almost unshakable belief that he is contaminating other people unless he washes his hands for three hours after urinating. However, the OCD patient with an overvalued idea can usually, after considerable discussion, acknowledge the possibility that his or her belief may be unfounded. In contrast, the person with a true delusion usually has a fixed conviction that cannot be shaken and also is likely to have other psychotic symptoms such as ideas of reference, paranoia, and/or hallucinations.

Tourette's disorder:

Obsessive compulsive disorder is often found in patients with Tourette's disorder and in that case both diagnoses are given. There is much confusion concerning terminology between neurologists, who often see Tourette's patients, and psychiatrists, who are more likely to see pure OCD patients. Often rituals are referred to as complex tics in the neurological literature.

Course and prognosis

The mean age of onset of OCD is between ages 20 and 24; over 80% develop symptoms prior to age 35. Some patients describe the onset of symptoms after a stressful event, such as a pregnancy, a sexual problem, or the death of a relative and in many cases the onset is acute. Because many patients manage to keep their symptoms secret, there is often a delay of 5 to 10 years before patients come to psychiatric/psychological attention.

Precise predictions of the general course and prognosis of OCD are precluded by the lack of detailed knowledge about the natural history of the illness. There are no carefully conducted studies that evaluate longitudinal course. In general, OCD is a chronic illness that exhibits a waxing and waning course, even with treatment. Although complete cures do occasionally occur, such an outcome is unusual. However, approximately 90% of patients can expect to have moderate to marked improvement with optimum treatment. There is some evidence that good premorbid functioning is an optimistic prognostic sign, but hard evidence of this is lacking. The actual obsessional content does not seem to be related to prognosis.

Failure to Improve:

Poor compliance with behavioural treatment instructions is the most common reason for treatment failure with behavioural therapy. Behaviour therapists make specific demands on the patients, and compliance with behavioural instructions both during treatment sessions and also during "homework" assignments is imperative if patients are to maximally improve. Inconsistent implementation of treatment recommendations is unlikely to be successful. Family members of friends often act as surrogate therapists in helping OCD patients to carry out homework assignments. The use of antiobsessional medications combined with behaviour therapy usually increases patients' compliance with exposure treatments.

Patients who hold very strong beliefs or so-called overvalued ideas that their compulsive rituals are in reality necessary to prevent some catastrophes seem to have a poor outcome with behavioural treatments. For example, the patient who really believes that her daughter will die if she does not wash all of her daughter's clothes every day is unlikely to give up washing rituals with behaviour therapy alone. Antiobsessional medication may produce changes in such fixed beliefs, and behaviour therapy may then by helpful.

In severely depressed patients, physiological habituation to a feared stimulus usually does not occur, regardless of the length of exposure, but such patients often respond well to behaviour therapy once depression is pharmacologically controlled.

Even when responsive to behavioural techniques, patients with checking rituals appear to respond more slowly than those with cleaning rituals. Many clinicians also feel that patients who are predominantly washers are easier to treat successfully than patients who check predominantly. Patients with checking rituals are often unable to engage in prescribed response prevention, especially those who check excessively at home. In addition, patients with primary obsessional slowness respond more slowly to behaviour therapy than do patients with either cleaning or checking rituals.


The treatment of patients suffering from OCD is a superb example of the need to integrate various approaches to maximise patient outcome. It is very unusual for OCD patients to respond fully to either psychotherapeutic or pharmacological approaches; and for optimal response, patients must generally receive medication in combination with other approaches, particularly behaviour therapy. This combined approach can be expected to improve the condition of most patients substantially, and occasionally completely, within a few months.


In the absence of any adequate studies of psychotherapy for OCD, it is difficult to make any valid generalisations about its effectiveness. Traditional psychodynamic psychotherapy is not currently considered an effective treatment for obsessions and/or rituals occurring in patients meeting criteria for OCD as defined in DSM-IV; there are no reports in the modern psychiatric literature of patients who stopped ritualising when treated with this method alone. Traditional psychodynamic psychotherapy, however, may be helpful for patients with obsessive compulsive personality disorder. Many traditional psychotherapists find themselves becoming more directive with OCD patients and thereby approach some of the techniques used by behaviour therapists.

Supportive psychotherapy is often helpful. Regular contact with a kind, warm, and understanding therapist can help the patient comply with behaviour therapy and medication side effects. Many OCD patients involve family members in their rituals and, even if this is not the case, families may be very troubled by the patient's behaviours. In addition, family members can be very helpful to the patient by being surrogate home behaviour therapists. Any psychotherapeutic endeavours must include attention to family members through the provision of emotional support, reassurance, explanation, and advice on how to manage and respond to the patient.


There are currently medications that predictably help over half of the OCD patients. Currently, pharmacotherapy (combined with behaviour therapy for patients with rituals) is considered the treatment of choice for OCD.

Cyclic and Atypical Antidepressants: recent studies have found that clomipramine - Anafranil (up to 250mg/day), sertraline - Zoloft (up to 200mg/day), paroxetine - Aropax (up to 60mg/day), and fluoxetine - Prozac (up to 80mg/day) are effective treatments for OCD.

The best studied antiobsessional agent is clomipramine, a tricyclic antidepressant that has been available in Europe and Canada for decades. It has specific antiobsessional properties apart from its antidepressant qualities. The optimum dose is unknown, but the majority of researchers feel dosage should be increased to 250mg/day if patients tolerate side effects. A large number of carefully controlled studies have confirmed preliminary results that clomipramine is indeed superior to placebo in the treatment of OCD. A large, very encouraging multicentre trial of clomipramine showed that almost 60% of patients on clomipramine had at least a moderate response with another 25% reporting at least some improvement. The main drawback to clomipramine is that at therapeutic doses it has some unwanted side effects. In addition, sexual difficulties are common and there is a small incidence of seizures at higher doses. Most patients, however, tolerate it well.


Guided surgery (stereotactic) to certain parts of the brain may be considered in certain severe cases resistant to all other treatments. There is research under way in this area.

Behaviour Therapy:

The behavioural techniques most consistently effective in reducing compulsive rituals and obsessive thoughts are exposure to the feared situation or object, and response/ritual prevention (ERP), in which the patient resists the urge to perform the compulsion after exposure. ERP begins with real life exposure to triggers that initiate the obsessive thought-compulsive behaviour pattern. This recreates the anxiety and distress that is felt due to the OCD symptom picture. At this point the typical ritual response is prevented and the patient remains in a state of distress.

With prolonged exposure to the triggering situation, unrelieved by compulsions, the patient habituates and his or her discomfort dissipates. Simple relaxation therapy is an ineffective treatment on its own for OCD symptoms. Behaviour therapy produces the largest changes in rituals, such as compulsive cleaning or checking, whereas changes in obsessive thoughts are less predictable. This difference reflects the specific effects of behavioural treatment, where the behaviours themselves are the targets of treatment. Consequently behaviour therapy is now regarded as the treatment of choice (in combination with pharmacotherapy) when behavioural rituals predominate.

Unfortunately, it was not until the late 1960's that Exposure Response Prevention therapy techniques were widely and effectively employed in the treatment of OCD. Inexperienced clinicians are sometimes fearful of the effects or unaware of the potential of behaviour therapy. A number of common misconceptions have developed. It is important for the clinician to know that behaviour therapy will not lead to the formation of substitute symptoms. Interrupting compulsive rituals is not dangerous in any way to the patient, the patient's thoughts and feelings are not ignored in behaviour therapy, and modern behaviour therapists do not assume that all maladaptive behaviour is learned through simple conditioning processes. The use of medication is not incompatible with behaviour therapy, and behaviour therapists recognise that their therapeutic techniques are not equally effective for all patients.

Controlled outcome studies of exposure and response prevention for OCD over the past 15 years with more than 200 patients in various countries have found that 60-70% of OCD patients had much improved after behavioural treatment.

Occasional studies have attempted to tease apart the differential effects of exposure and response prevention components of behaviour therapy. For example, with washers, exposure therapy was found to help mainly in reducing the anxiety component, while response prevention had its greatest effect in reducing the ritualistic washing. The combined treatment was more effective than either component in isolation.

In patients with checking rituals, combined imaginal exposure (i.e. having the patient vividly imagine the most feared consequences of not ritualising) plus response prevention is superior to response prevention alone. This approach is necessary for some patients because the catastrophic consequences that many checkers fear will never actually occur in real life, so habituation must be carried out in imagination.

There are a number of psychological and cognitive-behavioural techniques used to assist patients with obsessions. These involve cognitive re-attribution, postponing the worrying, changing the style of obsessing, distraction from the content of the obsession, satiation audio-loop tape exposure and mindful awareness techniques.


In summary, the effective behavioural treatment of OCD requires intensive intervention on the part of the therapist and often supportive friends or family. Understandably, it also requires strong motivation on the part of the patient.

The decision as to whether to combine pharmacotherapy and behavioural treatment should be made during consultation with the patient. Medication has shown to be an effective treatment and best results occur with the potent SSRI medications.

If a patient responds favourable to medication, maintenance therapy is indicated for an indefinite period of time. In the presence of severe major depressive illness, the decision is clear: a combined approach may be more effective. It is generally considered that medication therapy in the absence of behavioural therapy does not constitute an adequate nor appropriate treatment for OCD. Combined therapy works best with OCD.

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