schizophrenia

• Schizophrenia


  A mental disorder characterised by psychosis. Patients find it difficult to distinguish between reality and their own thoughts.
• Positive symptoms of schizophrenia


  • Hallucinations
  • Delusions
• Negative symptoms of schizophrenia

  • Speech poverty (alogia)
  • Avolition
• ICD-10/11 Classification System


  Used by World Health Organisation (WHO). Requires 2 or more negative symptoms for a diagnosis.
• DSM-V Classification System


  Used by American Psychiatric Association (APA). Requires one positive symptom for diagnosis.
• Reliability


  • Inter-rater reliability refers to the extent that two clinicians will reach the same diagnosis. Test-retest reliability is whether the same diagnosis is reached for the same individual on two occasions by one clinician.
• Historically, reliability has been low but recent studies suggest higher reliability. Osario et al. (2019) found inter-rater reliability of +.97 and +.92 for test-retest reliability.
• Validity


  Validity refers to the extent that a diagnosis represents something that is real and distinct from other disorders and whether the ICD or DSM measure what they claim to measure.
• Cheniaux et al. (2009) found that when two psychiatrists assessed the same clients using both ICD and DSM that 68 were diagnosed with the ICD and only 39 under the DSM. So, depending on the system used, Schizophrenia may be over or under diagnosed.
• Issues with reliability and validity of schizophrenia diagnosis

  • Co-morbidity
  • Gender bias
  • Symptom overlap
  • Culture bias
• Co-morbidity


  The extent to which two (or more) conditions occur at the same time in a patient. Schizophrenia is often diagnosed alongside other conditions, e.g., 50% also have depression, 47% substance abuse and 23% OCD (Buckley et. al, 2009). This makes diagnosis and treatment difficult, and schizophrenia may not even be a distinct disorder.
• Gender bias


  More men are diagnosed than women but this could be because women have more social support and so function better (Cotton et. al., 2009). This leads to underdiagnosis and a lack of treatment for women.
• Symptom overlap


  Many symptoms of Schizophrenia are also symptoms of other disorders, for example, bipolar disorder. Therefore, it could be that they are not two separate conditions but different variations of the same condition.
• Culture bias


  Symptoms can be interpreted differently in different cultures. African-Caribbean British people are 9 times more likely to be diagnosed than White British people. The diagnostic system may be culturally-biased.
• Biological explanations for schizophrenia

  • Genetics
  • Neural correlates
• Genetic explanations


  Family studies show increased risk in genetically related individuals. Candidate genes and mutations may also play a role.
• The fact that the concordance rate for twins is not 100% means that Schizophrenia cannot be accounted for by genetics alone. Environment also plays a role.
• Adoption studies have found a genetic basis, with higher concordance rates in identical twins compared to fraternal twins even when adopted.
• Neural correlates


  Abnormalities in brain regions like the ventral striatum, superior temporal gyrus and anterior cingulate gyrus are associated with schizophrenic symptoms.
• Dopamine hypothesis


  Excess dopamine in some pathways (hyperdopaminergia) can cause positive symptoms, while low dopamine in the prefrontal cortex (hypodopaminergia) can cause negative symptoms.
• Psychological explanations for schizophrenia

  • Family dysfunction
  • Cognitive explanations
• Family dysfunction explanations


  Schizophregenic mother, double-bind theory, and high expressed emotion in the family can contribute to the development of schizophrenia.
• The theories of schizophregenic mother and double bind have no systematic evidence to support them and are only based on informal assessments.
• Cognitive explanations


  Dysfunctions in metarepresentation (difficulty recognizing one's own thoughts/behaviors) and central control (inability to suppress automatic thoughts) can lead to symptoms like hallucinations and delusions.
• Treatments for schizophrenia


  • Drug therapy (typical and atypical antipsychotics)
  • Cognitive behaviour therapy
  • Family therapy
  • Token economies
• Diathesis-stress model


  An interactionist approach that explains schizophrenia as resulting from a genetic predisposition (diathesis) interacting with environmental stressors.
• Schizophrenics have more difficulty recognising that their own behaviours/thoughts are being carried out by themselves rather than another person
• Metarepresentation


  The first type of dysfunctional thought processing where there is difficulty recognising that one's own behaviours/thoughts are being carried out by oneself rather than another person
• Central control dysfunction


  The second type of dysfunctional thought processing where there is an inability to suppress automatic thoughts and the speech triggered by one's own thoughts
• PET scans show under activity in the frontal lobe of the brain which is linked to self-monitoring, which schizophrenics have less control over
• Schizophrenics took twice as long to complete the Stroop test suggesting impaired cognitive processing
• Cognitive explanations are good for explaining symptoms


  But there are also genetic origins for these impairments, so a more interactionist approach may be better
• Typical antipsychotics


  Created in the 1950s, taken orally, start low and work up to 400-800mg, reduce dopamine levels in the brain by blocking dopamine receptors, have a sedating effect
• Typical antipsychotics


  • Chlorpromazine, Pimozide
• Atypical antipsychotics


  Created in the 1970s, have less side effects than typical antipsychotics, can treat negative as well as positive symptoms by also acting on serotonin and glutamate receptors
• Atypical antipsychotics


  • Clozapine, Risperidone
• There are many side effects of antipsychotics including agitation, weight gain and tardive dyskinesia, which involves involuntary facial movements. Many stop taking the drugs because of this
• Clozapine is more effective than typical and other atypical antipsychotics, reducing symptoms in 30-50% of patients who did not improve with typical antipsychotics
• We do not fully understand why antipsychotic drugs work and recent research suggests that low levels rather than high levels of dopamine could cause schizophrenia and so they may not be the best treatment for all
• Cognitive Behaviour Therapy (CBT)


  Helps patients identify irrational thoughts and tries to change them, 5-20 sessions individually or as a group, explains to the patient where their symptoms come from and how this impacts their own feelings