Interactionist Approach

• The Interactionist Approach explains the development of behaviour in terms of a range of factors that combine in a way that can't be produced by each one separately
• The Diathesis-Stress model explains that behaviour is the result of both an underlying vulnerability (diathesis) and an environmental trigger (stressor)
• Meehl (1962) developed the original diathesis-stress model which stated that the diathesis was the result of one 'schizogene' without which no amount of stress could cause schizophrenia
• The modern diathesis-stress model explains that schizophrenia is aetiologically heterogenous and the diathesis can also include psychological trauma
• Read et.al. proposed a neurodevelopmental model in which early trauma alters the developing brain e.g. an overactive HPA system
• The modern diathesis-stress model explains that stress includes anything that risks triggering schizophrenia
• Cannabis use increases the risk of developing schizophrenia by up to seven times as it interferes with the dopamine system, acting as a stressor
• The interactionist approach has been applied to treatment as antipsychotic drugs are often combined with psychological therapy
• There is more conflict between biology and psychology in the US so combined treatment is less common
• There is research to support the interactionist approach e.g. Tienari et.al.
• Tienari et.al. conducted a study of 19,000 finish adoptees with biological mothers diagnosed with schizophrenia and compared them to a control group of adoptees with low genetic risk
• Tienari et.al. found that high levels of criticism & hostility and low levels of empathy were strongly associated with development of schizophrenia, but only in the high genetic risk group
• The original diathesis-stress model is criticised for being oversimplistic
• The diathesis-stress model has real-world applications as the combination of drug treatments and therapies enhances their effectiveness
• A limitation of the interactionist approach is treatment-causation fallacy, therefore we cannot assume that the success of combined therapies means that interactionisexplanations are correct
• Treatment-causation fallacy is the assumption that a successful treatment for a disorder justifies a particular explanation for it
• Urbanisation provides support for the interactionist approach as schizophrenia is more commonly diagnosed in urban areas, suggesting stressful living acts as a trigger
• A counterpoint to urbanisation is that schizophrenia may be more likely to be diagnosed in cities due to teenagers that have faced abuse in their childhood migrating to more urban areas