The essential feature of Obsessive Compulsive 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:

1. anankastic neurosis
2. obsessional neurosis
3. obsessive-compulsive neurosis