Mental health articles

CAUSES OF SCHIZOPHRENIA

There are a range of concepts regarding the causes of schizophrenia and much research, for example studies of twins, has been completed to try and establishthe main causes. Below are some of the main theories regarding the causes of schizophrenia.

GENETIC FACTORS

Schizophrenia is more likely to occur in a family with a person with schizophrenia. If a sibling has been diagnosed with schizophrenia, there is an 8% risk for another sibling to experience schizophrenia. If one parent has schizophrenia, there is a13% risk; if both parents have schizophrenia, there is a 40% risk that a child will experience the disorder. However, this evidence is not strong enough to suggest that schizophrenia is a genetic disorder but only that genetics may play a part in the development of the disorder.

BIOLOGICAL FACTORS

Eby and Brown  state that there are differences in the structural, chemical and functional aspects of the brains of people with schizophrenia. One particular idea that supports the use of antipsychotic medications is that people with schizophrenia havean excess of the brain chemical dopamine which can be reduced with antipsychoticmedication by blocking the neurotransmitter that produces it. This is why some people taking antipsychotic medication experience stiffness, lack of movement or abnormal movements similar to those seen in Parkinson’s disease, as Parkinson’sdisease is caused by a reduction of dopamine in the brain.

ENVIRONMENTAL FACTORS

Semple et al. report that complications during the mother’s pregnancy and a subsequent traumatic delivery of the baby who endures injury have been found to be associated with a risk of developing schizophrenia. Eby and Brown suggest that people with schizophrenia tend to be born in winter andspring. This has led to a belief that the mother of the person with schizophrenia contracted a maternal viral infection (influenza) that may have affected the infant. This may link to the fact that most people raised in an urban area have a greater risk for developing the disorder as viral infection is more prevalent in urban areas.

PSYCHOLOGICAL FACTORS

In the late 1950s, Brown) discovered that people with schizophrenia discharged from a psychiatric hospital to live with their family or a relative were more likely to suffer a relapse in their condition than those who were discharged to live alone or without family members. This led to a discovery that a person with schizophrenia may live in a family who are highly critical, hostile and overinvolved.These families are described as having high expressed emotion. Vaughn and Leff discovered that when people with schizophrenia were discharged home after a recovery from their symptoms to these families they were more likely to become unwell again even though they were taking medication. Whereas a person with schizophrenia who returned to a family with low expressed emotion was morelikely to stay well. These concepts have led to the development of psychosocial interventions and are discussed further in this chapter and also in Chapter 14 of thistext.

The stress vulnerability model developed by Zubin and Spring  suggests that people with schizophrenia have genetic and biological vulnerabilities to personal, familial and environmental stressors and that this theory is a way of explaining the onset of schizophrenia and any relapses; therefore, strategies are required to help reduce the impact of stress on them, for example improving coping skills. A result of this is that the person with schizophrenia may feel more equippedto deal with their personal, familial and environmental stressors and less likely to suffer a relapse in their condition.

A study in Edinburgh in 2005 demonstrated:

People in high-risk categories for schizophrenia go on to develop the disease, show subtleand early warning signs that distinguish them from others in their group..

The study, which began in 1994, tracked 163 young adults identified as ‘at risk’of schizophrenia (based on the fact that each subject had two relatives diagnosedwith schizophrenia). According to the data, those in this group who developed schizophrenia had more prediagnosed anxiety, social withdrawal and schizotypal thoughts than those who remained well. Such early symptoms were subtle in nature,tending not to be debilitating to daily life.

Given that such problems may develop slowly over several years before they become debilitating, this strongly supports the benefits of early screening, identification and treatment of those who are at genetic and/or environmental risk of developing schizophrenia.

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