interactionist approach

• The interactionist approach (a.k.a the biosocial model)

  to schizophrenia acknowledges the that a range of biological, psychological and societal factors are involved in the development of schizophrenia.
• The diathesis-stress model is an interactionist approach which suggests SZ is the result of both an underlying vulnerability (diathesis) and a stress-trigger.
• Meehls model (original stress diathesis model)

  Diathesis – entirely genetic and the result of a ‘schizogene’

  Stress – stress through childhood and adolescence

  If you do not have the schizogene, no amount of stress leads to SZ
• Modern understanding:

  Our understanding has changed

  Diathesis – many genes increase genetic vulnerability and there is no ‘schizogene’. It can also be psychological trauma

  Stress – anything that risks triggering SZ e.g. parenting, cannabis use (increases risk 7x)  etc
• strength

  There is clear evidence to show that environmental factors also increase the risk of SZ e.g family and cognitive dysfunction. The fact that concordance rate in MZ twins who share all of their genes was not 100% suggests other factors must play a role. Genetic factors alone cannot provide a complete explanation for SZ, supporting an interactionist approach.
• strength

  Tienari (2004) – studied 19,000 adopted Finish children whose biological mothers had SZ and compared them to control children. They found that adoptive parents with high levels of criticism and hostility were strongly associated with SZ development, but only in the genetic risk group.Shows a combination of genetic vulnerability and family stress can lead to an increased risk of SZ, supporting an interactionist approach
• weakness

  The original diathesis stress model portrayed diathesis as a single schizogene and stress as schizophrenogenic parenting, however research has shown multiple gene influence diathesis and stress can come in many forms. The original diathesis-stress model was over simplistic and there is evidence to support the modern understanding of stress and diathesis.
• As the interactionist model acknowledges both biological and psychological factors, it combines both antipsychotic medication and psychological therapies (usually CBT).
• strength

  Tarrier – randomly allocated 315 pp’s to either a medication and CBT treatment plan or just medication and found those with a combined approach showed lower symptoms (however no difference was seen in hospital readmission rates.) Clear practical advantage to adopting an interactionist approach to treatment