Possible causes of schizophrenia

The causes of mental illness are linked to several factors which can be summarised into three main groups:

• Biological factors which arise from physiology, biochemistry, genetic make-up and physical constitution
• Psychological factors including the person's upbringing, emotional experiences and interactions with people
• Social factors that are associated with the person's present life situation and sociocultural influences

No single cause of schizophrenia has been identified to date; there are most likely to be several contributing factors. It is probable that there is an interaction between the consumer's biological vulnerability, stress or change in the environment and the consumer's ability to deal with these environmental factors in terms of their social skills and supports. If the environment is sufficiently stressful, even people with a high personal threshold for stress will develop some indicators of mental illness, including schizophrenia. Conversely, a less stressful environment may decrease the risk of onset in a person with a predisposition to schizophrenia.

We know that schizophrenia is NOT caused by:

• Domineering mothers or passive fathers
• Poverty
• Weakness of character or personality
• Bad parenting
• Sinful behaviour

Possible Contributing Factors:

Genetics

Twin, family and adoptions studies suggest that genetic factors play an important role in the development of schizophrenia. For example, the child of one parent with schizophrenia has about a 10 per cent chance of developing schizophrenia; if both parents have schizophrenia, the risk is increased to 40 per cent. By comparison, the risk of schizophrenia in the general population is about one per cent. The list below indicates the chances of developing schizophrenia during a life time:

• General Population 1%
• Brother or sister has schizophrenia 8-10%
• One parent has schizophrenia 12-15%
• raternal twin has schizophrenia 14%
• Idential twin has schizophrenia 50%

Environment

Possible environmental factors include obstetric complications such as exposure to influenza during pregnancy or nutritional deprivation during pregnancy. It has also been suggested that stress and trauma can lead to the emergence of schizophrenia. Family factors causing stress may affect the course of the illness but there is no convincing evidence that they have a causative role.

Neurodevelopmental Factors

The research in this area investigates the possibility that individuals who develop schizophrenia in early adult life have suffered some from of cerebral maldevelopment in utero. That is, they experience a disorder in the development of their brain while in the womb.

Drug Misuse

Although contentious, some research suggests that substance misuse is related to the development of schizophrenia. It is likely that substance misuse may precipitate or worsen the symptoms and interfere in the treatment of a person with schizophrenia.

Biochemical Factors

Certain biochemical imbalances in the brain are believed to be involved in the cause of schizophrenia. Neurotransmitters (the substances that allow communication between nerve cells) have long been thought to be involved in the development of schizophrenia. Although there are no definitive answers yet, this is a very active area of schizophrenia research.