F42 Obsessive-Compulsive Disorder

The essential feature of this disorder is recurrent obsessional thoughts or compulsive acts. (For brevity, "obsessional" will be used subsequently in place of "obsessive-compulsive" when referring to symptoms.) Obsessional thoughts are ideas, images or impulses that enter the individual's mind again and again in a stereotyped form. They are almost invariably distressing (because they are violent or obscene, or simply because they are perceived as senseless) and the sufferer often tries, unsuccessfully, to resist them. They are, however, recognized as the individual's own thoughts, even though they are involuntary and often repugnant. Compulsive acts or rituals are stereotyped behaviours that are repeated again and again. They are not inherently enjoyable, nor do they result in the completion of inherently useful tasks. The individual often views them as preventing some objectively unlikely event, often involving harm to or caused by himself or herself. Usually, though not invariably, this behaviour is recognized by the individual as pointless or ineffectual and repeated attempts are made to resist it; in very long-standing cases, resistance may be minimal. Autonomic anxiety symptoms are often present, but distressing feelings of internal or psychic tension without obvious autonomic arousal are also common. There is a close relationship between obsessional symptoms, particularly obsessional thoughts, and depression. Individuals with obsessive-compulsive disorder often have depressive symptoms, and patients suffering from recurrent depressive disorder may develop obsessional thoughts during their episodes of depression. In either situation, increases or decreases in the severity of the depressive symptoms are generally accompanied by parallel changes in the severity of the obsessional symptoms.

Obsessive-compulsive disorder is equally common in men and women, and there are often prominent anankastic features in the underlying personality. Onset is usually in childhood or early adult life. The course is variable and more likely to be chronic in the absence of significant depressive symptoms.

Diagnostic Guidelines

For a definite diagnosis, obsessional symptoms or compulsive acts, or both, must be present on most days for at least 2 successive weeks and be a source of distress or interference with activities. The obsessional symptoms should have the following characteristics:

(a) they must be recognized as the individual's own thoughts or impulses:
(b) there must be at least one thought or act that is still resisted unsuccessfully, even though others may be present which the sufferer no longer resists;
(c) the thought of carrying out the act must not in itself be pleasurable (simple relief of tension or anxiety is not regarded as pleasure in this sense);
(d) the thoughts, images, or impulses must be unpleasantly repetitive.

Includes:
* anankastic neurosis
* obsessional neurosis
* obsessive-compulsive neurosis

Differential Diagnosis
Differentiating between obsessive-compulsive disorder and a depressive disorder may be difficult because these two types of symptoms so frequently occur together. In an acute episode of disorder, precedence should be given to the symptoms that developed first; when both types are present but neither predominates, it is usually best to regard the depression as primary.

In chronic disorders the symptoms that most frequently persist in the absence of the other should be given priority.

Occasional panic attacks or mild phobic symptoms are no bar to the diagnosis. However, obsessional symptoms developing in the presence of schizophrenia, Tourette's syndrome, or organic mental disorder should be regarded as part of these conditions.

Although obsessional thoughts and compulsive acts commonly coexist, it is useful to be able to specify one set of symptoms as predominant in some individuals, since they may respond to different treatments.

F42.0 Predominantly Obsessional Thoughts Or Ruminations

These may take the form of ideas, mental images, or impulses to act. They are very variable in content but nearly always distressing to the individual. A woman may be tormented, for example, by a fear that she might eventually be unable to resist an impulse to kill the child she loves, or by the obscene or blasphemous and ego-alien quality of a recurrent mental image. Sometimes the ideas are merely futile, involving an endless and quasi-philosophical consideration of imponderable alternatives. This indecisive consideration of alternatives is an important element in many other obsessional ruminations and is often associated with an inability to make trivial but necessary decisions in day-to-day living.

The relationship between obsessional ruminations and depression is particularly close: a diagnosis of obsessive-compulsive disorder should be preferred only if ruminations arise or persist in the absence of a depressive disorder.

F42.1 Predominantly Compulsive Acts (Obsessional Rituals)

The majority of compulsive acts are concerned with cleaning (particularly hand-washing), repeated checking to ensure that a potentially dangerous situation has not been allowed to develop, or orderliness and tidiness. Underlying the overt behaviour is a fear, usually of danger either to or caused by the patient, and the ritual act is an ineffectual or symbolic attempt to avert that danger. Compulsive ritual acts may occupy many hours every day and are sometimes associated with marked indecisiveness and slowness. Overall, they are equally common in the two sexes but hand-washing rituals are more common in women and slowness without repetition is more common in men.

Compulsive ritual acts are less closely associated with depression than obsessional thoughts and are more readily amenable to behavioural therapies.