INTERACTIONIST APPROACH IN EXPLAINING + TREATING SCHIZOPHRENIA
Sz depends on biological factors (genetics, neurochemicals) + psychological factors (stress)
Diathesis model
SUPPORTING STUDY - TIENARI (2004)
METHOD USED TO ASSESS ADOPTIVE FAMILY FUNCTIONING = ONLY ASSESSED AT ONE POINT IN TIME
ORIGINAL MODEL = OVER-SIMPLIFIED
- Diathesis refers to vulnerability
- Stress - refers to a negative psychological experience
- Interactionist approach states that both stress + genes are needed in order to develop the condition
- We must be genetically vulnerable but the onset of the condition is triggered by stress
' Schizogene'
- Without this gene, no amount of stress would lead to Sz, however if you carried the gene, some stress in childhood (e.g. a schizophrenogenic mother) could trigger the condition
- Original diathesis model states there is a 'schizogene'
- Modern understanding indicates there is no one single 'schizogene' + many genes increase genetic vulnerability
- It is now thought that psychological trauma in childhood e.g. sexual abuse, can also affect brain development + may therefore be a diathesis
- This again indicates that both biology + environment may play a role in the condition
Stress can occur in a number of forms
- E.g. childhood trauma/living in an urbanised environment
- Severe trauma before the age of 16 makes you 3 times as likely to develop Sz later in life + the level of trauma is closely linked to severity of symptoms
- Modern view of stress = not just psychological - cannabis use increases the risk of Sz 7 times according to the dose as cannabis interferes with the dopamine system
- Most individuals who smoke cannabis don't develop te disorder but it is a risk factor + demonstrates once again that the onset of the disorder most likely requires stress (e.g. cannabis) but also genetic vulnerability
- Investigated 20,000 Finnish women admitted to psychiatric hospitals diagnosed with Sz + had their offspring adopted away (high risk group), these were compared with adoptees without this genetic risk (low risk)
- Results = out of the 303 adoptees, 14 developed Schizophrenia + 11 were from the high risk group and being reared in a 'healthy' adoptive family had a protective effect on high risk group
- This shows that genetic vulnerability + family related stress are important in the development of Sz
- it is now understood that multiple genes increase vulnerability with each having a small effect + stress can come in many forms, not just parenting
- Houston states that vulnerability can now be a result of childhood sexual abuse + cannabis is the trigger
- It is clear that it is not just the diathesis being biological + stress being psychological
- However, fortunately newer models have addressed this issue
- This fails to reflect developmental changes in family functioning over time
- What is also not clear is how much stress is caused by the family + how much stress is caused by the adoptee themselves
- This questions the validity of the evidence that supports the interactionist approach for Sz
Genetic vulnerability
- Shown in twin studies
- Joseph pooled data for all Sz twin studies
- Found that concordance rates = 40.4% for monozygotic twins + only 7.4% for dizygotic twins
- However, for 60% of identical twins in which one twin is diagnosed, the other never meets the diagnostic criteria for Sz
- This indicates that the environment must pay a role in the development of Sz alongside genetic factors
Treatment
- Interactionist because it combines biological + psychological treatments e.g. CBT + antipsychotics
- Britain = interactionist approach
- USA = conflict over interactionist approach with antipsychotics being the preferred choice
- However, it is unusual to treat Sz only using psychological therapies + interactionist approach to treatment is often adopted successfully
SUPPORTING STUDY - TARRIER ET AL (2004)
- Patients in the two combination groups shower lower symptom levels than those in the control group (medication only) - but no difference in hosptial readmission
- This shows that there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes
- Randomly allocated 315 patients to a medication + CBT group, a medication + supportive counselling group, or a control group