schizophrenia

Mental disorder, a psychosis of unknown origin, which can lead to profound changes in personality, behaviour, and perception, including delusions and hallucinations. It is more common in males and the early-onset form is more severe than when the illness develops in later life. Modern treatment approaches include drugs, family therapy, stress reduction, and rehabilitation.

Schizophrenia implies a severe divorce from reality in the patient's thinking. Although the causes are poorly understood, it is now recognized as an organic disease, associated with structural anomalies in the brain. There is some evidence that early trauma, either in the womb or during delivery, may play a part in causation. There is also a genetic contribution: a gene linked to schizophrenia was identified in 2000.

According to a survey published in August 2001, there were an estimated 60 million schizophrenics worldwide. The prevalence of schizophrenia in Europe was about two to five cases per 1,000 of the population. There is an enormous variation between countries in the symptoms of schizophrenia and in the incidence of the main forms of the disease, according to a 1997 report by US investigators. Paranoid schizophrenia, characterized by a feeling of persecution, is 50% more common in developed countries, whereas catatonic schizophrenia, characterized by total immobility, is six times more frequent in developing countries. Hebephrenic schizophrenia, characterized by disorganized behaviour and speech and emotional bluntness, is four times more prevalent in developed countries overall but is rare in the USA.

Research findings
Canadian researchers in 1995 identified a protein in the brain, PSA-NCAM, that plays a part in filtering sensory information. The protein is significantly reduced in the brains of schizophrenics, supporting the idea that schizophrenia occurs when the brain is overwhelmed by sensory information. In 1997, US researchers linked schizophrenia to a mutation in the gene that codes for an acetylcholine receptor. The receptor, α7-nictotinic receptor, is also stimulated by nicotine.