7. interactionist approach

what is the interactionist approach

interactionist approach = way to explain development of behaviour in terms of a range of factors including both biological and psychological ones

• the factors dont simply add together, but combine in a way that cant be predicted by each one seperately ie they interact

examples of factors for schizophrenia

• biological = genetic vulnerability, neurochemical and neurological abnormality

• psychological = stress ie from life events and daily hassles including social factors such as poor quality interactions in the family

a way to present the interactionist approach

diathesis stress model = explains how schizophrenia results from the interaction between a person’s genetic predisposition and exposure to stressful life events

original model

meehl’s model was entirely genetic with the result of a ‘schizogene’

• led to idea of a biologically based schizotype personality - a characteristic of which is sensitivity to stress 

• if a person did now have the schizogene then no amount of stress would lead to szhiophrenia

modern understanding of the diathesis

1. many genes each appear to increase genetic vulnerability only slightly as there is no single schizogene

2. there is a range of factors beyond the genetic including psychological trauma so that becomes the diathesis rather than the stressor

3. neurodevelopmental model

neurodevelopmental model 

read et al 

• early trauma (ie child abuse) alters the developing brain 

• for example the HPA system can become overactive making a person much more vulnerable to later stress

modern understanding of stress

• recent research into factors has concerned cannabis use 

• regarding diathesis stress model, its a stressor as it increases the risk of schizophrenia by up to 7x - may be because it interferes with the dopamine system 

treatment according to the interactionist model

associated with combining antipsychotic medication and psychological therapies ie CBT

• this is more common in the UK than US 

• UK = increasingly standard practice to treat with a combination of antipsychotic drugs and CBT 

• US = more of a history of conflict between psychological and biological models leading to a slower adoption of an interactionist approach 

evaluation

1. support for vulnerability and triggers

2. real world application (& COUNTERPOINT)

3. urbanisation

support for vulnerability and triggers

• strong evidence supporting idea both genetic vulnerability and environmental stress contribute 

• tienari studied adopted children of biological mothers with schizophrenia and found children were more likely to develop schizophrenia when raised in families which high levels of criticism and conflict compared to those in low stress ones - shows it results from an interaction between genetic vulnerability (diathesis) and stressful family environments (stress)

• thus model is supported by real world evidence showing both factors play a role

real world application

• clear practical benefits in treatment 

• studies have shown combining biological (antipsychotic meds) and psychological therapies (CBT) leads to better outcomes than either alone

• highlights how model has real world value as it informs integrated treatment approaches that acknowledge both biological and environmental influences 

counterpoint

• hard to establish causation between vulnerability and stress

• unclear whether biological abnormalities (ie dopamine dysregulation) cause stress and psychosis or whether chronic stress leads to biological changes - challenges assumption the diathesis always precedes stress

• thus while a comprehensive model, may not fully capture the complex and reciprocal nature of schizophrenias causes 

urbanisation

• rates of schizophrenia are higher in urban areas than rural ones supporting role of environmental stress

• stressful urban living (noise, social isolation, pollution) may act as a trigger in genetically vulnerable individuals

• further supports interactionist view that both environmental and biological factors interact in the development of schizophrenia