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Schizophrenia - Coggle Diagram

- - - - Lack of inter-rater reliability - despite the claims for increased reliability in DSM-III , over 30 years later there is still little evidence that DSM is routinely used with high reliability by mental health clinicians. For example, Whaley (2001) found inter-rater reliability correlations in the diagnosis of schizophrenia as low as 0.11.
      - Unreliable symptoms - For diagnosis of 'schizophrenia', only one of the characteristic symptoms is required 'if delusions are bizarre'. However, this creates problems for reliability of diagnosis. For example, when 50 senior psychiatrist in the US were asked to differentiate 'bizarre' and 'non-bizarre' delusions. they produced inter-rater reliability correlations of only around 0.40 (Mojtabi and Nicholson, 1995).
      - A comment on cultural differences in the diagnosis of schizophrenia - Research (e.g. Barnes, 2004) has established cultural, and racial, differences in the diagnosis of schizophrenia. However, the prognosis for members of ethnic minority groups may be more positive than for majority group members.
  - - - Research support for gender bias in diagnosis - Loring and Powell (1988) found evidence of gender bias among psychiatrists in the diagnosis of schizophrenia.
      - The consequences of co-morbidity - A number of studies have examined single comorbidities with Schizophrenia, but these studies have usually involved only relatively small smaple size.
      - Difference in prognosis - In the same way that people diagnosed as schizophrenic rarely share the same symptoms, likewise there is no evidence that they share the same outcomes.
- - - - Evaluation: MZ twins encounter more similar environments - A crucial assumption underlying all twin studies is that the environments of MZ twins and DZ twins are equivalent. Joseph (2004) points out that MZ twins are treated more similarly, encounter more similar environments and experience more 'identity confusion'.
    - - Evaluation: Adoptees many be selectively placed - an assumption studies is that adoptees are not 'selectively placed', i.e. adoptive parents who adopt children with a schizophrenic biological parent are no different to adoptive parents who adopt children whose background is normal.
  - - - Drugs that increase dopaminergic activity - Amphetamine is a dopamine agonist, i.e. it stimulates nerve cells containing dopamine, causing the synapse to be flooded with this neurotransmitter.
      - Drugs that decrease dopaminergic activity - Although there are many different types of antipsychotic drugs, they all have one thing in common, i.e. they block the activity of dopamine in the brain. By reducing activity in the neural pathways of the brain that use dopamine as the neurotransmitter, these drugs eliminate symptoms such as hallucinations and delusions.
      - The revised dopamine hypothesis - Davis and Khan (1991) proposed that the positive symptoms of schizophrenia are caused by an excess of dopamine in subcortical areas of the brain, particularly in the mesolimbic pathway. The negative and cognitive symptoms of schizophrenia are thought to arise from a deficit of dopamine in areas of the prefrontal cortex (the mesocortical pathway).
      - Evidence from treatment: Much of the evidence supporting the dopamine hypothesis comes from the success of drug treatments that attempt to change levels of dopamine activity in the brain.
      - Challenges to the dopamine hypothesis: Noll (2009) claims there is strong evidence against both the original dopamine hypothesis and the revised dopamine hypothesis.
  - - - Implications for treatment: The importance of neural correlates for schizophrenia is that early intervention might prevent development of the later stages of this disorder.
- - - - These errors are not corrected by disconfirming evidence because patients with schizophrenia do not go through the same processes of reality testing that other would do.
  - - - Evaluation - Not all patients who live in high EE families relapse, and not all patients who live in low EE homes avoid relapse. Altorfer et al. (1998) found that one-quarter of the patients they studied showed no physiological responses to stressful comments from their relatives
    - - Evaluation - There is some evidence to support this particular account of how family relationships may lead to schizophrenia. Berger (1965) found that schizophrenics reported a higher recall of double bind statements by their mothers than non-schizophrenics. However, other studies are less supportive. Gibney (2006) claims that the real value of double bind theory is that it led to the development of family therapy.
- - - - Procedure cont. - Both groups of adoptees were independently assessed after a median interval of 12 years, with a follow-up after 21 years. Psychiatrists also assessed family functioning in the adoptive families using the OPAS (Oulu Family Rating Scale). This scale measures families in various aspects of functioning such as parent-offspring conflict, lack of empathy and insecurity. The interviewing psychiatrists were kept blind as to the status of the biological mother (i.e. schizophrenia or no schizophrenia).
      - Findings - Of the 3003 adoptees, 14 had developed schizophrenia over the course of the study. 11 were from the high-risk group (i.e. those with mothers previously diagnosed with schizophrenia or paranoid psychoses) and three were from the low-risk group (i.e. the control group adoptees). However, being reared in a 'healthy' adoptive family (low OPAS ratings) appeared to have a protective effect even for those at high genetic risk for schizophrenia. High-genetic-risk adopted reared in families with low OPAS ratings were significantly less likely to have developed schizophrenia than high-genetic risk adoptees reared in families with high OPAS ratings. In adoptees at high genetic risk of schizophrenia, but not in those at low genetic risk, adoptive-family stress was a significant predictor of the development of schizophrenia.
    - - Most diathesis-stress models emphasise 'vulnerability' in terms of genetic influences alone, which are assumed to cause neurochemical abnormalities that, in turn, result in an increased risk for schizophrenia. Verdoux et al. (1998) estimated that the risk of developing schizophrenia schizophrenia later in life for individuals who have experienced obstetric complications at birth is 4 times greater than those who experience no such complications.
      - Romans-Clarkson et al. (1990) found no urban-rural differences in mental health among women in New Zealand despite Vassos et al. saying otherwise.
      - Doathesis-stress models make reference to stressful events that occur close to the onset of schizophrenia, but it is possible that stressors earlier in life can also influence how people respond to later stressful events and increase their future susceptibility to the disorder.
      - Limitations in the Tienari et al. such as psychiatrists assessed stress in the adoptive family using the OPAS scale, they were assessing family functioning only at one given point in time.
      - Borglum et al. (2014) found that women infected with cytomegalovirus during pregnancy were more likely to have a child who developed schizophrenia, but only if both mother and child carried a particular gene defect.