The interactionist approach

What is the interactionist approach?

Acknowledges there are biological, psychological and societal factors in the development of SZ

Biological = genetic vulnerability and neurochemical and neurological abnormality

Psychological = stress resulting from life events and daily hassles including poor quality interactions in the family

The diathesis stress model

• a vulnerabilty to SZ and a stress trigger are necessary to develop SZ

• One are more underlying factor make a person vulnerable but the onset of the condition is triggered by stresses

What is meant by the terms diathesis and stress?

This model explains that individuals will develop SZ if they have a biological predisposition and if they are exposed to stressful situations

Diathesis - a predisposition to develop a medical condition

Stress - any environmental factor that could trigger the disorder

Plus both of them = schizophrenia

Meehls original model

• believed diathesis was entirely genetic, the result of a single ‘schizogene’

• This led to the development of a biologically based schizotypic personality, one characteristic is sensitivity to stress

• According to Meehl, if a person doesn’t have the schizogene then no amount of stress would lead to SZ. However in carriers of the gene, chronic stress through childhood and adolescence, particularly a SZ mother could result in SZ.

Modern understanding of diathesis

• now clear that many genes increase genetic vulnerability. There is no single ‘schizogene’

• Modern views recognise diathesis is not exclusively genetic and includes a range of factors including psychological trauma

• So trauma can become the diathesis rather than the stressor

• Read proposed a neurodevelopmental model in which early trauma alters the developing brain. Eg: the hypothalamic-pituitary- adrenal system becomes over active and the person is more vulnerable to later stress

• According to a 2006 study by NIH, trauma mainly affects development of three important parts of your brain; the amygdala, your emotional and instinctual centre; the hippocampus which controls memory and the PFC responsible for regulating emotions and impulses

• So amygdala goes into overdrive becoming overly sensitive, PFC cannot suppress fear/make relational decisions and the hippocampus perceives everything as a threat

Early understanding of stress

• in the original diathesis stress model stress was seen as psychological in nature and particularly related to childhood

• Varies et al found that children who experienced severe trauma before the age of 16 were 3x more likely to develop schizophrenia in later life compared to the general population

• There was a relationship between the level of trauma and likelihood of developing schizophrenia, with those serverly traumatised as a child being at greater risk

The original diathesis stress model oversimplifies

• idea of a single schizogene and schizophrenic parenting style as the major source for stress is oversimplified the original model that portrayed diathesis as due to a schizogene and stress due to childhood being oversimplified

• Multiple genes increase vulnerability, there is no single gene

• Stress can also come in many forms not just dysfunctional parenting

• Now believed vulnerability can be caused by early trauma as well as genetic makeup and stress can come in many forms including biological

RWA; support fro combo treatments

• standard practise in the UK is to combine the drugs and CBT/family therapy. Turkington et al point out that it is perfectly possible to believe in biological causes and still practice CBT to relieve symptoms

• Terrier (2004) 315 patients were randomly allocated to a medication + CBT group, medication + supportive counselling or a control group

• Patients in the two combination groups showed lower symptom levels than control, although there was no difference in rates of hospital readmission

• This and other studies show that there is clear advantage to adopting an interactionist approach

• Although combining therapies increases the cost of treatment, the greater effectiveness can make combination therapies more cost effective in the long term

We don’t know exactly how diathesis and stress work

• strong evidence to suggest some sort of underlying vulnerability coupled with stress can lead to SZ

• Also have well informed suggestions for how vulnerabilities and stress might lead to symptoms

• However we do not yet fully understand the mechanisms by which the symptoms of SZ appear and how both vulnerability and stress produces them

• Eg: diathesis - stress models typically focus on stressful events that occur close to the onset of schizophrenia (eg; cannabis ), but it may be possible that maladaptive methods of coping with stress developed ad children affects resilience in later life.