Interactionist Approach to Schizophrenia

The Interactionist Approach to Schizophrenia

- acknowledges the biological, psychological and social factors of schizophrenia

- e.g. genetic vulnerability, stress, interactions in the family

Diathesis-Stress Model of Schizophrenia

- diathesis = vulnerability

- stress = negative experience

- both a vulnerability to schizophrenia and a stress-trigger are needed to develop the disorder

- one or more underlying factors may make a person vulnerable to schizophrenia but the onset of the condition is triggered by stress

Meehl's Model of Schizophrenia (1962)

- diathesis was entirely genetic caused by a single 'schizogene'

- this led to a schizotypic personality characterised by sensitivity to stress

- this is what causes schizophrenia but not sufficient for its development; if a person doesn't have this gene no amount of stress can cause schizophrenia

- if carriers of the gene chronic stress throughout childhood and adolescence (particularly a schizophrenogenic mother) can cause the disorder

Modern Understanding of Diathesis

- it has now been shown that schizophrenia is polygenic and is caused by no one gene (Ripke et al, 2014)

- each gene only appears to increase genetic vulnerability slightly

- psychological trauma is also viewed as a diathesis as well as a stressor

- (Read, 2001) proposed a neurodevelopmental model in which early trauma alters the developing brain

- e.g. trauma like child abuse can make the hypothalamic-pituitary-adrenal system (HPA) overactive making a person more vulnerable to stress

Modern Understanding of Stress

- the modern definition is no longer just psychological in nature but now includes anything that risks triggering stress (Houston et al, 2008)

- cannabis use has been implicated in causing schizophrenic episodes

- cannabis is a stressor because it increases the risk of schizophrenia up to 7x according to dose

- this may be because cannabis interferes with the dopamine system

- however most people don' t develop schizophrenia after taking cannabis because they don't have the vulnerability factors

Treatment According to the interactionist Model

- as the model acknowledges biological and psychological factors it combines both types of treatment

- the model is associated with combing anti-psychotic drugs and psychological therapies e.g. CBT

- in Britain it is increasingly standard practice to use a combination of antipsychotic drugs and CBT

- in the US there is more conflict between the biological and psychological models of schizophrenia which has led to a slower adoption of the interactionist model

- this means that drug treatment without psychological therapy is more common in the US

Support for Vulnerability: Strength

- (Tienari et al, 2004) investigated the impact of both genetic vulnerability and a psychological trigger (dysfunctional parenting)

- 19,000 Finnish children whose biological mothers had schizophrenia were monitored

- the genetic risk group was compared to the control group of adoptees who didn't have a family history of schizophrenia

- child-rearing styles typified by high levels of criticism, hostility and low levels of empathy were associated with the development of schizophrenia but only in high genetic risk group

Diathesis & Stress are Complex: Limitation

- the original diathesis-stress model is oversimplified

- multiple genes in multiple combinations influence diathesis and stress comes in many forms, including but not limited to dysfunctional parenting

- diathesis can also be influenced by psychological factors and stress can be biological as well as psychological

- (Houston et al, 2008) found child sexual abuse as a major influence on underlying vulnerability and cannabis was the major trigger

- this means multiple factors affect diathesis and stress , supporting the modern model

Real-World Application: Strength

- acknowledging both biological and psychological factors in schizophrenia has been combining drug and psychological therapy

- studies have shown that using both enhances their effectiveness

- (Tarrier al, 2004) randomly allocated 315 participants to either:
. medication & CBT
. medication & counselling
. control group (medication only)

- participants in the 2 combination groups showed lower symptoms than the medication only group following the trial

- this means there is a clear practical advantage to adopting an interactionist approach to schizophrenia

Real-World Application: Counterpoint

- (Jarvis & Okami, 2019) point of saying successful treatment for a mental disorder justifies a particular treatment is the logical equivalent of saying because alcohol reduces shyness, shyness is caused by lack of alcohol

- this logical error is called the treatment-causation fallacy

- we cannot automatically assume the success of combined therapies means interactionist explanations are correct

Urbanisation: Evaluation Extra

- schizophrenia is more commonly diagnosed in urban rather than rural areas

- this supports the interactionist position as it assumes that urban living is more stressful than rural, therefore city livening acts a trigger

- however it may simply be that schizophrenia is more likely to be diagnosed in cities

- or people with diathesis for schizophrenia (e.g. teenagers abused as children) tend to migrate to cities