Possible 'causes' of Schizophrenia

There is no known single cause of schizophrenia. Many diseases, such as heart disease, result from a number of genetic, behavioural, and other factors; and this may be the case for schizophrenia as well. We do not yet understand all of the factors necessary to produce schizophrenia, but experts do agree that the disease is due to abnormalities of brain function, some of which have been detected. Schizophrenia is a disease of the mind, the symptoms of which are attributed to abnormalities in the transfer and processing of information within the brain. Nerve cells in the brain communicate with each other by releasing chemicals (called neurotransmitters) from their nerve endings. Many of the symptoms of schizophrenia have been linked to abnormalities in the activity of particular neurotransmitters, particularly two known as 'dopamine' and 'serotonin'. For the majority of people the treatment of schizophrenia relies on drugs (known as neuroleptics or antipsychotics), which modify the effects of many of these neurotransmitters in the brain.

The cause of schizophrenia includes many factors, and these causal factors lead to certain individuals becoming more vulnerable to psychotic symptoms. This vulnerability may be triggered by a variety of life events and situations, particularly around early adulthood. They may include the stress of going to university, starting work, developing close personal relationships and generally the stresses of developing an adult life style. Bereavements, family break-ups and changes to financial and social circumstances may also have an impact.

Street drugs including cannabis have been associated with the triggering of schizophrenia and temporary psychotic symptoms. There is ongoing debate and research looking at a more direct causal link with cannabis use; that is to say, that rather than just triggering schizophrenia it may be one of the factors in causing the illness when used in late childhood and early teens.

There is a higher proportion of cannabis use amongst those with a diagnosis of schizophrenia than the general population. This may be an attempt to self medicate or to reduce the distressing effect of social isolation and not feeling part of everyday life. The use of cannabis in this way can lead to an increase in symptoms, plus further social isolation. Dual diagnosis is a term used when an individual uses street drugs, such as cannabis, and is receiving treatment for mental illness. More mental health teams are employing a specific worker to deal with the issue of dual diagnosis.