The Interactionist Approach to Schizophrenia

Interactionist approaches attempt to explain schizophrenia as a combination of nature (biological) and nurture (environmental) factors.

Meehl (1962) originally proposed that both a vulnerability to schizophrenia and a stress-trigger are necessary in order to develop the condition.

Meehl suggested that the vulnerability is genetic (the result of a 'schizogene'), causing a sensitive personality. 

Chronic environmental stress, for example, having a schizophrenogenic mother, results in the onset of schizophrenia, even if they experienced a chronically stressful upbringing.

Both aspects of diathesis-stress must be present to develop the disorder.

The modern understanding of diathesis-stress is slightly different. It is now recognised that the vulnerability could be genetic or environmental (for example, a traumatic event in early childhood). The stress-trigger could be environmental or biological (for example, smoking cannabis is linked with schizophrenia).

In an interactionist approach, treatments will take more than one form.

Antipsychotic medication will often be used alongside CBT, acknowledging the role that biological and psychological factors play in the disorder.

Combining treatments is most common in the UK, although it is also sometimes used in the USA.

Psychological therapies are very rarely used alone, but sometimes patients may just take drugs without any other therapy.

+ Tienari et al (2004) found that children from adopted families who had mothers with schizophrenia were more likely to develop schizophrenia themselves, but only in those whose adopted families were assessed as having a child-rearing style which was critical and lacking in empathy. This supports the diathesis-stress model, as the genetic vulnerability only led to the disorder when combined with an environmental stressor (critical family).

+ Tarrier et al (2004) found that patients who were treated with drug therapy and CBT showed lower symptom levels than those only taking drugs, supporting the interactionist approach in explaining schizophrenia.

- There is a lack of understanding and explanation of how the diathesis-stress model works - it is known that both have to be present to lead to schizophrenia, but not how the mechanisms of schizophrenia symptoms develop. This weakens the interactionist approach.