Hypochondriasis is a preoccupation with physical signs or symptoms that the patient unrealistically interprets as abnormal, leading to the fear or belief that he is seriously ill.

There may be fears about the development of physical or mental symptoms without any such existing, a belief that actual but minor symptoms are of dire consequence, or an experience of normal bodily sensations as threatening symptoms.

A thorough physical examination may find no organic cause for the physical signs the patient is concerned about, but the examination fails to relieve his unrealistic fears about having a serious disease.

The symptoms of hypochondriasis may occur with mental illnesses other than neuroses, for instance, depression or schizophrenia.

Hypochondriacal neurosis occurs in both sexes.

The onset may be associated with precipitating factors such as an actual organic disease with physical and psychological aftereffects; e.g., coronary thrombosis in a previously fit man.

It often begins during the fourth and fifth decades of life but is also common at other times, during pregnancy, for example.

Treatment aims to provide understanding and support and to reinforce healthy behaviour; antidepressant drugs may be used when there are depressive symptoms.

Other somatoform disorders

In psychogenic pain disorder the main feature is the persistent complaint of pain in the absence of organic disease and with evidence of a psychological cause.

The pattern of pain may not conform to the known anatomic distribution of the nervous system. Psychogenic pain may occur as part of hypochondriasis or as a symptom of a depressive disorder. Appropriate treatment depends on the context of the symptom.

These somatoform disorders may occur together in one patient. Alternatively, they may occur in atypical form or in association with another physical or mental illness.

Dissociative disorders or hysterical neurosis, dissociative type

Dissociation is a syndrome in which one or a group of mental processes are split off, or dissociated, from the rest of the psychic apparatus so that their function is lost, altered, or impaired.

Dissociative symptoms have often been regarded as the mental counterparts of the physical symptoms displayed in conversion disorders.

Since the dissociation may be an unconscious mental attempt to protect the individual from threatening impulses or emotions that are repressed, the conversion into physical symptoms and the dissociation of mental processes can be seen as related defense mechanisms arising in response to emotional conflict.

In dissociative disorders there is a sudden, temporary alteration in the person's consciousness, sense of identity, or motor behaviour.

There may be an apparent loss of memory of previous activities or important personal events, with amnesia for the episode itself after recovery. These are rare conditions, and it is important to exclude organic causes.

In psychogenic or hysterical amnesia there is a sudden loss of memory which may appear total; the patient can remember nothing about his previous life or even his name.

The amnesia may be localized to a short period of time associated with a traumatic event or it may be selective, affecting the person's recall of some, but not all, of the events during a particular time.

In psychogenic fugue, the individual wanders away from his home or place of work and assumes a new identity; he cannot remember his previous identity and upon recovering cannot recall the events that occurred while he was in the fugue state.

In many cases the disturbance lasts only a few hours or days and involves only limited travel. Severe stress frequently triggers this disorder.

Multiple personality is a rare and remarkable dissociative disorder in which two or more distinct and independent personalities develop in a single individual.

Each of these personalities inhabits the person's conscious awareness to the exclusion of the others at particular times.

This disorder frequently arises as a result of traumas suffered during childhood and is best treated by psychotherapy, which seeks to reunite the various personalities into a single, integrated one.

In depersonalization a person feels or perceives his body or self as being unreal, strange, altered in quality, or distant. This state of self-estrangement may take the form of feeling as if one is machinelike, is living in a dream, or is not in control of one's actions.

Derealization, or feelings of unreality concerning objects outside one's self, often occurs at the same time. Depersonalization may occur alone in neurotic patients but is more often associated with phobic, anxiety, or depressive symptoms.

It most commonly occurs in younger married women and may persist for many years.

Patients find the experience of depersonalization intensely difficult to describe and often fear that people will think them insane.

Organic conditions, especially temporal lobe epilepsy, must be excluded before making a diagnosis of neurosis when depersonalization occurs.

As with other neurotic syndromes, it is more common to see a mixed picture with many different symptoms than depersonalization alone.

The causes of depersonalization are obscure, and there is no specific treatment for it.

When the symptom arises in the context of another psychiatric condition, treatment is aimed at that illness.