A01

• 1. The interactionist approach explains how biological, psychological and societal factors interact in the development of schizophrenia. An example of this is the diathesis-stress model, where vulnerability and stress are both necessary for the disorder to develop.
• 2. The original model explained how diathesis was purely genetic (a single ‘schizogene’), without which schizophrenia would not develop. Chronic childhood and adolescence stress (i.e. schizophrenogenic mother) could result in the development of the disorder.
• 3. Our improved understanding of diathesis is that there are actually many genes that increase genetic vulnerability. Diathesis can even include psychological trauma as it can alter the developing brain in ways that can make a person more vulnerable to later stress. Similarly, stress has changed to include anything that risks triggering schizophrenia, such as cannabis use which can increase the risk of up to seven times depending on the dose.
• 4. In terms of treatment, the interactionist approach combines antipsychotics with psychological therapies, most commonly CBT. In the UK, it is unusual to treat schizophrenia using psychological treatments alone as they are usually used alongside antipsychotic