Interactionist Approach

• the traditional view - Meehl's model

  • diathesis stress model
  • genes interact with life experience and environment
  • a schizogene existed in the population and if that individual carrying the gene experienced trauma or inconsistent parenting, then schizophrenia would emerge
• the modern view - diathesis

  • there is no single schizogene, but views of diathesis also include a range of factors beyond the genetic, including psychological trauma
  • the trauma becomes the diathesis rather than the stressor
• pre-existing vulnerability and premorbid period

  • impacts during pregnancy (e.g. infection, nicotine, alcohol)
  • labour/birth complications
  • genetic risk
  • age of father
  • early trauma
• neurodevelopmental alterations - diathesis

  • abnormal brain development
  • neurotransmitter abnormalities
  • puberty
• the modern view - stress

  • stress was seen as psychological in nature
  • in the modern definition ofstress it includes anything that risks triggering schizophrenia
• neurodevelopmental alterations - stress

  • overactive stress system
  • epigenetics
• psychosis progression

  • life stressors (e.g. moving our, bereavement, divorce etc)
  • drug use (may interfere with neurotransmitter systems)
  • first psychotic episode
  • diagnosis
  • chronic illness
• additivity

  • schizophrenia is triggered by the sum of diathesis and stress, so a high predisposition can be triggered by a small stress, whereas a low predisposition may require many small stressors or a large stressor
• interactionist treatment

  • drugs and therapy
  • interactionist treatments follow the biopsychosocial model and consider the combined or total impact of therapy (holistic)
  • they acknlowledge multiple approaches and the interactions between them
  • for example, combination therapy - drugs plus psychosocial intervention (usually CBT)
• evidence for the role of multiple factors - Teinari et al

  • investigated how biological factors moderate susceptibility to environment risks associated with family life
  • children adopted from 19 000 Finnish mothers with schizophrenia
  • child rearing style of adoptive mothers was assessed
  • longitudinal and compared against a control group with no generic risk
  • interviewers were blind to mothers' diagnosis status
  • those in the high genetic risk group were significantly more likely to develop schizophrenia but only if their adoptive parents; child rearing style was high in criticism and low in empathy
• evidence for interactionist treatments

  Tarrier et al (2004)

  • randomly allocated 315 patients to one of three groups
  • drugs + CBT, supportive therapy ot a control group (drugs only)
  • 18 month follow up - patients in the two combination groups showed lower symptom levels than the control group
  • there was no difference in rates of hospital readmissions
  • findings differed between hospitals included in the study