There is an inherited element: parents, children or siblings of schizophrenic sufferers have a one in ten chance of developing the disorder; a twin has a 50 per cent chance if the other twin has schizophrenia. Some BRAIN disorders such as temporal lobe EPILEPSY, tumours and ENCEPHALITIS seem to be linked with schizophrenia. Certain drugs - for example, AMPHETAMINES - can precipitate schizophrenia and DOPAMINE-blocking drugs often relieve schizophrenic symptoms. Stress may worsen schizophrenia and recreational drugs may trigger an attack.

These usually develop gradually until the individual's behaviour becomes so disturbing or debilitating that work, relationships and basic activities such as eating and sleeping are interrupted. The patient may have disturbed perception with auditory HALLUCINATIONS, illogical thought-processes and DELUSIONS; low-key emotions (‘flat affect’); a sense of being invaded or controlled by outside forces; a lack of INSIGHT and inability to acknowledge reality; lethargy and/or agitation; a disrespect for personal appearance and hygiene; and a tendency to act strangely. Violence is rare although some sufferers commit violent acts which they believe their ‘inner voices’ have commanded.

Relatives and friends may try to cope with the affected person at home, but as severe episodes may last several months and require regular administration of powerful drugs - patients are not always good at taking their medication -hospital admission may be necessary.

So far there is no cure for schizophrenia. Since the 1950s, however, a group of drugs called antipsychotics - also described as NEUROLEPTICS or major tranquillisers - have relieved florid symptoms such as thought disorder, hallucinations and delusions as well as preventing relapses, thus allowing many people to leave psychiatric hospitals and live more independently outside. Only some of these drugs have a tranquillising effect, but their sedative properties can calm patients with an acute attack. CHLOR-PROMAZINE is one such drug and is commonly used when treatment starts, or to deal with an emergency. Halperidol, trifluoperazine and pimozide are other drugs in the group; these have less sedative effects so are useful in treating those whose prominent symptoms are apathy and lethargy.

The antipsychotics’ mode of action is by blocking the activity of DOPAMINE, the chemical messenger in the brain that is faulty in schizophrenia. The drugs delay the onset and prolong the remission of the disorder, and it is very important that patients take them indefinitely. This is easier to ensure when a patient is in hospital or in a stable domestic environment.

Newer drugs (known as atypical antipsy-chotics) may be less likely to cause unwanted effects so they are now considered for use in newly-diagnosed schizophrenia or in other patients responding poorly to the standard agents or those who suffer untoward effects from them.

The welcome long-term shift of mentally ill patients from large hospitals to community care (often in small units) has, because of a lack of resources, led to some schizophrenic patients not being properly supervised with the result that they fail to take their medication regularly. This leads to a recurrence of symptoms and there have been occasional episodes of such patients in community care becoming a danger to themselves and to the public.

The antipsychotic drugs are powerful agents and have a range of potentially troubling side-effects. These include blurred vision, constipation, dizziness, dry mouth, limb restlessness, shaking, stiffness, weight gain, and in the long term, TARDIVE DYSKINESIA (abnormal movements and walking) which affects about 20 per cent of those under treatment. Some drugs can be given by long-term depot injection: these include compounds of flupenthixol, zuclopenthixol and haloperidol.

About 25 per cent of sufferers recover fully from their first attack. Another 25 per cent are disabled by chronic schizophrenia, never recover and are unable to live independently. The remainder are between these extremes. There is a high risk of suicide.