There have been many theories to try to explain schizophrenia. The cause is not known, but certain things have been found to be different in people who develop schizophrenia: these include:

• The brain structure of people with schizophrenia may be abnormal.
• Subtle blood flow changes in certain parts of the brain.
• Shortage of certain brain chemical receptor molecules in these parts of the brain.
• Enlarged lateral ventricles (the fluid-filled spaces in the brain).
• Abnormal nerve pathway connections in part of the brain.
• There is evidence that, in predisposed people, schizophrenia can be triggered by stressful experiences and possibly by some recreational drugs such as cannabis and cocaine.
• Studies suggest that it runs in families, but the risk of getting schizophrenia, if a family member has it, is still relatively small.

A psychiatrist will diagnose schizophrenia when there is evidence of a profound break in reality manifesting itself in one or more of the following symptoms for several months:

• Thought insertion: the belief that someone is putting thoughts into the persons head.
• Thought broadcasting: the belief that others can hear the persons thoughts as they occur.
• Feelings of passivity: the belief that the persons thoughts and actions are being controlled by someone else.
• Hearing voices commenting on the persons actions.
• Other delusional beliefs out of the blue.
• Physical hallucinations: for example that someone is sitting on the person during the night.

Medical treatments

Most people with schizophrenia are prescribed drugs, which seek to reduce the positive symptoms. The drugs used for schizophrenia are antipsychotics or neuroleptics (major tranquillizers). The two major groups of antipsychotics are typical and atypical antipsychotics. Antipsychotic drugs can take between one and three months to take effect.  The typical antipsychotics are taken as tablets or syrup. Some are available as longer-lasting depo injections. Antipsychotics can have a range of side effects. These can be unpleasant. The most severe include muscle spasms, unusual body movements and acute movement disorders. The side effects of atypical antipsychotics are milder than typical antipsychotics, but they are more expensive.

Non-drug treatments

Talking therapies such as counselling and psychotherapy may be helpful for both people with schizophrenia and their families. These talking treatments are mostly used alongside drug treatment for people with schizophrenia. Support and self-help groups can also help.  Cognitive behavioural therapy (CBT) has been used successfully for the symptoms of schizophrenia such as delusions or hallucinations. There is some evidence that alternative therapies including exercise, art/music therapy changing diet/nutrition, homeopathy and herbal remedies have been found helpful in people with schizophrenia. Sometimes, people in an acute phase of the illness may need to be admitted to hospital under the Mental Health Act for assessment and/or treatment without consent. This is called sectioning. In many cases the person with schizophrenia will admit themselves to hospital if necessary, however most people with schizophrenia live in the community and many only see their doctor when they need a prescription. Many people with schizophrenia now carry Crisis Cards or set up Advance Directives, which make their treatment wishes known if they have to be admitted to hospital.

The major complications are to quality of life:

• An acute psychotic illness can be a terrifying experience - the hallucinations and delusions seem utterly real while they are being experienced.
• Social functions, such as being able to maintain personal relationships, ability to work and manage ones day-to-day life, are often seriously damaged.
• Suicide and self-harm are common in those with a diagnosis of schizophrenia: around 1 in 10 ultimately take their own life.
• Some of the drugs given to people with schizophrenia cause distressing side effects such as movement disorders, weight gain and sedation.

The information shown here is Crown copyright and has been reproduced with the permission of NHS Direct. Last updated June 2007.