Interactionist explanation for schizophrenia

Interactionist explanation

Acknowledges that a range of biological, psychological and societal factors are involved in the development of schizophrenia

Diathesis-stress model

schizophrenia is argued to be the result of both an underlying genetic vulnerability (diathesis) and an environmental trigger (stress). Both are necessary for the onset of schizophrenia

Meehl’s 1962 diathesis-stress model

The diathesis (vulnerability) for schizophrenia is entirely genetic. Genes are assumed to cause neurochemical abnormalities that in turn, result in an increased risk for schizophrenia

If a person does not have the genetic vulnerability, no amount of stress would lead to schizophrenia

The stress (trigger) for schizophrenia is negative psychological experience

Chronic stress in someone who carries the genetic vulnerability could result in schizophrenia

It is thought that diathesis ad stress add together is some way to produce schizophrenia (additive)

Modern understanding of diathesis

• polygenic (ripke 2014)

• Includes many psych factors including trauma as diathesis not stressor

Read et al 2001 – neurodevelopmental model in which early trauma alters the developing brain

HPA system can become overactive making a person more vulnerable to stress

• Cannabis use: increases risk up to 7 times and interferes with dopamine system

• Living in a highly urbanised environment

Vassos 2012 – risk of SCZ in urban environment estimated to be 2.4 times higher than rural could be due to adverse living conditions

Treatment

Combining both drug therapies and CBT is most effective

Terrier 1998 – patients with combined treatment as opposed to one or the other half a significant improve in the severity/number of positive symptoms.

Suggests it is more effective than the usual treatment plan of giving drugs alone