the interactionist approach

• what is the diathesis-stress model?

  a model that suggests that certain individuals have a constitutional pre-disposition to the disorder but will only develop it if exposed to stressful situations. in this, stressful events act as a trigger
• socio-cultural factors

  high stress levels associated with the onset of schizophrenia. its widely thought that this is due to physiological changes in the body when coping with stress that alter neurotransmitter levels
• evaluation of life events as a cause of schizophrenia

  the only research into this is correlational
• socio-cultural factors- poverty / social class

  schizophrenia occurs more in lower socio-economic groups. this could be that low socio-economic state is a risk factor in schizophrenia or people with schizophrenia lose jobs and can't adequately function, causing poverty.

  however, there's little evidence for the social drift hypothesis

  stress + poverty = schizophrenia
• Meehl


  suggested that diathesis was entirely genetic as the result of a single schizo-gene. he said that if someone didn't have the gene, they couldn't develop it despite stress

  Meehl has been criticised for being too simple and has been revised after discovering that schizophrenia is polygenic. a range of factors cause the diathesis, including physical and psychological trauam. cannabis use increases likelihood by up to seven times
• Brzustowicz et al-


  early trauma [a threat to physical, emotional, or sexual integrety under 19 years old] was significantly associated with expression of schizophrenia in families demonstrating genetic predisposition to schizophrenia
• Tienari et al-


  investigated combination of genetic vulnerability and parenting style in children adopted from Finnish mothers with schizophrenia. Adoptive parents were assessed for child-rearing and the rates of schizophrenia were compared to those in a control group of adoptees without any genetic risk. child rearing style with high levels of criticism and conflict and low levels of empathy appeared to be associated with developing schizophrenia. This supports the interactionist explanation that both genetic vulnerability and family stress are important in the developing schizophrenia
• Walker


  reported that schizophrenics have higher levels of cortisol than non-sufferers and that cortisol levels are related to severity of sumptoms. with stress-related increases to cortisol levels heightening genetic influenced abnormalities in dopamine transmission that underpin schizophrenia vulnerability. this triggers onset. this shows the interaction between biological and environmental factors
• Murray


  children who were born after the flu epidemic whose mothers had caught the flu during the second trimester of pregnancy were 88% more likely to develop schizophrenia since its thought that this causes defects in neural development. causing brain damage which increases vulnerability and dopamine levels
• Cannon et al


  reviewed available evidence and found a positive correlation between birth complications and later vulnerability to developing schizophrenia. some indication of damage to hormone and neurotransmitter systems, as well as immune systems
• Barlow and Durand


  reported that a family history of schizophrenia coupled with being part of a dysfunctional stressor elevated the risk of developing schizophrenia
• evaluation

  elevated cortissol levels may be an effect rather than a factor causing schizophrenia
• evaluation

  walker reports that cortisol levels are higher immediately before onset of schizophrenia, rather than during recovery. this supports the hypothesis
• evaluation

  its not known precisely how risks [biologicsl, environment, social etc] contribute to the diathesis-stress model for any one person. it may differ between individuals
• evaluation

  differential suspectability hypothesis expands on the diathesis stress model to include positive environments reudicng the chance of schizophrenia
• evaluation

  genes can't determine outcomes alone, they need a particular environment to express themselves in line with the model