Interactionist approach to schizophrenia

Interactionist approach

Way to explain development of schizophrenia using a range of factors including biological and psychological ones

Meehl’s model - original diathesis stress model

Diathesis (vulnerability) was entirely genetic, the result of a single schizogene

• If a person does not have the schizogene then no amount of stress would lead to schizophrenia

• In carriers of gene, chronic stress through childhood could lead to development of schizophrenia

Modern understanding of diathesis

No schizogene, many genes increase genetic vulnerability

Also include more than genetic factors such as psychological trauma, so trauma becomes diathesis rather than stressor. Early trauma may alter a developing brain

Modern understanding of stress

Modern definition includes anything that risks triggering schizophrenia - Houston et al

An example of a stressor is cannabis because it increases risk of schizophrenia by up to 7 times as it interferes with dopamine system

Treatment according to interactionist model

Combines antipsychotic medication with CBT

Turkington et al - in order to practise CBT you have to have an interactionist model as you cannot tell people their condition is purely biological and then treat them with CBT

Increasingly standard practise in UK

Evaluation of interactionist approach

+ Tarrier et al

Randomly allocated participants to 3 groups (medication and CBT,medication and counselling, Control group).Participants in 2 combo groups showed lower symptoms post trial

Evaluation of interactionist approach

+ Tienari et al

Followed 19,000 finish children whose biological mothers had schizophrenia. Compared to control group of adoptees without it. Parents with high levels of criticism and hostility were strongly associated with development of schizphrnia but only in high genetic risk group. Supports vulnerability and stressors

Evaluation of interactionist approach

- Negatives

Oversimplicity in original model - Multiple genes in multiple combos influence diathesis and stress comes in many forms. Supports new model as both biological and psychological factors affect diathesis and stress

Successful treatment does not mean explanation was correct