the importance of the interactionist approach in explaining and treating schizophrenia - the diathesis stress model

what is the interactionist approach to schizophrenia

• explains schizophrenia in terms of the interplay of biological psychological and societal factors that are associated w its development rather than any one causal factor

• brings both nature and nurture equally

• biological - genetic vulnerability + abnormalities in neuroanatomy and neurochemistry

• psychological - stress + nature of interpersonal relationships

• societal - levels of deprivation, inequality and population crowding

• most well known interactionist approach is the diathesis stress model

what is the diathesis stress model

• diathesis - means vulnerability

• traditionally understood to be a genetic predisposition towards developing the disorder that is then triggered by negative life events

• both of these factors are needed for the disorder to occur

• Meehl (1962)

• there are many genes which each slightly predispose an individual to schizophrenia

• it is likely that the genes involved in teh model are linked to the neural abnormalities that correlate w symptoms of s

• chronic stress such as poor communication in families (double bind or expressed emotion) may then trigger the disorder due to the impact it has on the body

• long-term stress causes prolonged release of cortisol which is detrimental to physical and mental health

• possible that these excessive levels of cortisol are what cause the onset of schizophrenic episodes

how does the interactionist model treat schizophrenia ?

• in the uk treatments typically combine antipsychotics and CBT

• antipsychotics reduce the disordered thinking and make the benefits of CBT more accessible to the patient

• drug therapy is begun before psychological therapy so that symptoms are lessened before the sessions with therapist commence

nature of drug treatments in the interactionist model

• usually consists of typical antipsychotics such as chlorpromazine

• acts as a dopamine antagonist and works by binding to dopamine receptors on postsynaptic neurons impeding the action of dopamine in the brain

• only if resistant to typical antipsychotics will atypical antipsychotics like clozapine be used

• these are still dopamine antagonists though to a lesser extent but also bind to serotonin and glutamate receptors working more effectively to sooth symptoms - but produce worse side effects

nature of psychological therapy in the interactionist model

• once antipsychotics have taken effect the psychological therapy will begin and the two treatments are used in tandem

• in CBT patient will be encouraged to dispute faulty thinking that can lead to negative consequences where as in family therapy the focus will be on psychoeducation and teaching the close relations how to communicate better with them and how to access support if they themselves need

• it is very rare that psychological therapy is used w/o drug therapy

interactionist approach A+E point 1 - supporting evidence for explanation

The interactionist approach is strengthened by considerable evidence supporting the idea that both biological vulnerability and environmental stressors play a role in developing schizophrenia.

• Tienari et al (2004) - out of 19000 Finnish children adopted from mothers with schizophrenia, those placed in adoptive homes with child-rearing styles characterised by hostility and criticism were more likely to develop schizophrenia than those in homes with alternate child-rearing styles.

• these adoptees were compared with a control group with no genetic risk factor, and the same pattern was not seen: the adopted children placed in highly critical homes did not have an increased risk of developing schizophrenia.

• strongly suggests that both a genetic vulnerability and a psychological source of stress is required for the disorder to develop, as only those children who were more likely to have inherited genes predisposing them to develop schizophrenia did so as a result of the stressful home environments- without a genetic predisposition did not.

• Furthermore, the children who were likely to have inherited genes that predisposed them to develop schizophrenia who were not placed in stressful home environments also did not develop the disorder.

• Hence, both a genetic tendency and environmental stressors seem necessary for an individual to develop schizophrenia.

interactionist approach A+E point 2 - supporting evidence for interactionist treatments

The interactionist approach is also strengthened by the weight of supportive evidence for interactionist treatments for schizophrenia.

• Xiong et al (1994) and Leff et al (1985) - patients were far less prone to relapse when receiving family therapy in tandem with antipsychotics.

• Tarrier et al (2000) found that 33% of patients, receiving a combination of 2 sessions of PT (Personal Therapy - a specific type of CBT) each week for 10 weeks and drug therapy, had a 50% reduction in psychotic experiences. 15% reported that they were completely free of all positive symptoms!

• Importantly, both groups receiving a combination of psychological and drug therapies showed lower symptom levels than those in the medication-only condition.

• So, as treatment which uses both types of therapies is clearly superior in terms of patient outcomes to therapy which focuses on either one, this suggests we must not underestimate the importance of taking an interactionist approach in treating - or explaining - schizophrenia.

interactionist approach A+E point 3 - ‘treatment-causation fallacy’

However, we must be careful not to fall into the ‘treatment-causation fallacy’ when assessing the strength of the interactionist approach to schizophrenia.

• Simply because the effect of combining drug and psychological therapies provides better treatment for patients than either alone, we cannot assume that this means the interactionist explanation of schizophrenia is correct.

• It is possible that this just provides a better way of managing / alleviating symptoms and that we are still quite far from discovering any causal factors in schizophrenia.

• We cannot lose sight of this, as no current treatments offer any hope to patients of guaranteed cure without relapse; if we could find a cause behind any of the forms of schizophrenia, we would be better placed to develop a therapy that might offer such hope.