Schizophrenia - The interactionist approach + Drug therapy Flashcards
The interactionist approach
acknowledges that there are biological, psychological and societal factors in the development of schizophrenia
The diathesis-stress model
Diathesis means vulnerability
The diathesis-stress model says both a vulnerability to schizophrenia and a stress-trigger (environmental factor) are necessary in order to develop the conditon
Meehl’s model
Diathesis (vulnerability) was entirely genetic and the result of a single ‘schizogene’
If a person did not have the gene, they would not be able to develop schizophrenia regardless of how much stress they were exposed to
If someone did have the gene, chronic stress through childhood and adolescence, in particular the presence of a schizophrenogenic mother would trigger the gene and result in schizophrenia.
The modern understanding of schizophrenia
There is no single ‘schizogene’ and many genes appear to increase genetic vulberability
In the ordinal diathesis-stress model, stress was seen as psychological in nature but a modern definition of stress includes anything that risks triggering schizophrenia: so in terms of the diathesis-stress model smoking cannabis is a stressor because it increases the risk of schizophrenia by seven times due to interference with the dopamine system
Treatment according to the interactionist model
Standard practice to to treat people with a combination of CBT and antipsychotics
Tarrier et al
Tarrier et al conducted a study where 315 people with schizophrenia were randomly allocated to a medication + CBT group and a control group of medication only.
Results = people in the combination group showed lower symptom levels than those in the control group so there is a clear practical advantage to adopting an interactionalist approach
Incomplete understanding of how diathesis and stress work
Despite strong evidence to suggest vulnerability combined with stress lead to schizophrenia, there is no understanding of how symptoms of schizophrenia appear and how both vulnerability and stress produce them
Turkington et al
argue that just because combined biological and psychological treatments are more effective than either on their own does not mean the interactionalist approach is correct.
Similarly, the fact that drugs help does not mean that schizophrenia is biological in orgin - this error in logical is called the treatment-causation fallacy
Tienari et al
investigated the combination of genetic vulnerability and parenting style (the trigger).
Children adopted from 19,000 Finish mothers with schizophrenia were followed up and their adoptive parent’s child-rearing style was assessed
A child-rearing style characterised by high levels of criticism/conflict and low levels of empathy was implicated in the development of schizophrenia but only for children with high genetic risk and not in the control group
This suggests that genetic vulnerability and family related stress are important.
Typical antipsychotics - Chlorpromazine
The dopamine hypothesis of schizophrenia suggests: a dysregulated dopamine system contributes to positive, negative, and cognitive symptoms of the disease
APs work by acting as antagonists in the dopamine system: dopamine antagonists block dopamine receptors in the synapses of the brain reducing the action of dopamine
Atypical antipsychotics - Clozapine
aim to improve the effectiveness of drugs in supressing symptoms of schizophrenia but also minimise side effects
Binds to dopamine receptors (in the same way as Chlorpromazine) but also acts on serotonin and glutamate receptors which helps improve mood and reduce depression and anxiety in people
Typical strength - Thornley et al
Thornley et al reviewed studies comparing the effects of Chlorpromazine to a placebo
Data from 13 trials of 1121 participants showed chlorpromazine was associated with better overall functioning and reduced symptom severity.
Data from participants also showed relapse rate was lower when Chlorpromazine was taken
Atypical strength - Meltzer
concluded clozapine is more effective
Found in 30-50% treatment-resistant cases where typical antipsychotics have failed, clozapine was effective
Evaluation for drugs
Antipsychotic drugs are highly effective as they are relatively cheap to produce, easy to administer and have a positive effect on many sufferers.
However they do not “cure” schizophrenia, rather they dampen symptoms down so that patients can live fairly normal lives in the community therefore making life more manageable and improving the quality of life
Typical sideffects
dizziness, agitation and itchy skin.
long term = tardive dyskinesa (involuntaty facial movements) caused by dopamine sensitivity
