The interactionist approach to schizophrenia

Diathesis stress model

Meehl & Rosenthal

States that both a vulnerability to schizophrenia AND an environmental stimulus are needed to develop schizophrenia. Neither of them alone means that you will get schizophrenia, as it is the interaction that is key.

Meehl

Schizogene

Meehl originally suggested that diathesis was down to a singular ‘schizogene’, Meehl said that someone without this gene should never develop schizophrenia, regardless of the amount of stress they were exposed to.

But a person who does have the gene is more vulnerable to chronic stress.

Modern diathesis understanding

It has been stated that schizophrenia is not developed due to one singular gene, but that it is developed as a result of multiple genes, each having a small effect on diathesis.

Researchers believe that diathesis doesn’t have to be genetic and can also be as a result of environmental stimuli that damage or effect the brain or its development.

E.G. child abuse affects the hypothalamic-pituitary-adrenal system, making a child vulnerable to stress.

Treatment of schizophrenia using an interactionist model

Anti-psychotic medication taken in combination with CBT involves telling patients that their condition is purely biological but also treat them with CBT.

In Britain it is increasingly standard practice to treat psychological patients with a combination of drugs and CBT. In the US there is more of a conflict between psychological and biological models of schizophrenia and this may have led to slower adoption of the interactionist approach.

There is support for the role of vulnerability and stress in schizophrenia 🙂

Tienari et.al studied children adopted away from mothers diagnosed with schizophrenia

The original diathesis-stress model is over simplistic ☹

Multiple genes increase vulnerability, each with a small effect of its own - there is not a singular schizogene, and stress comes in many different forms.

Researchers now believe stress can also include biological factors. For example, Houston et.al found childhood sexual trauma was a diathesis and cannabis use was a trigger.

This means that there are multiple factors, biological and psychological, affecting both diathesis and stress.