Schiz

• Schizophrenia


  A psychotic disorder marked by severely impaired thinking, emotions, and behaviours. Schizophrenic patients are typically unable to filter sensory stimuli and may have enhanced perceptions of sounds, colours, and other features of their environment
• Symptoms of schizophrenia


  • Positive symptoms
  • Negative symptoms
• Positive symptoms


  Enhance the typical experience of sufferers, and occur in addition to their normal experiences e.g. hallucinations and delusions
• Negative symptoms


  Take away from the typical experience of sufferers, and so represents a 'loss' of experience e.g. speech poverty and avolition
• Hallucinations


  A positive symptom of schizophrenia, which is characterised by a distorted view/perception of real stimuli or perceptions of stimuli which have no basis in reality
• Delusions


  A positive symptom of schizophrenia and are a set of beliefs with no basis in reality at all
• Speech poverty


  A negative symptom of schizophrenia which occurs when there is an abnormally low level of the frequency and quality of speech
• Avolition


  A subjective reduction in interests, desires and goals and a behavioural reduction of self-initiated and purposeful acts, including motivational deficits
• Classification systems for mental disorders

  • Diagnostic and Statistical Manual (DSM-V)
  • International Classification of Disease (ICD-10)
• Differences between DSM and ICD

  • DSM has more specific diagnostic criteria and requires at least 2 or more of delusions, hallucinations, disorganized speech and catatonic behaviour, whereas the ICD-10 takes a broader approach to diagnosis
  • DSM and ICD are produced by different organisations (WHO or American Psychiatric Association)
  • DSM and ICD recognise different subtypes of schizophrenia
• Subtypes of schizophrenia


  • Positive schizophrenia
  • Mixed schizophrenia
• There is a significant co-morbidity (high frequency of diagnosis of two disorders together) between schizophrenia and other mental health disorders, such as OCD and post-traumatic stress disorder
• The high co-morbidity between schizophrenia and depression suggests that these two disorders may actually be the same, and so a more accurate and valid method of diagnosis would be to combine these two
• There may be gender bias in the diagnosis of schizophrenia, as suggested by the sudden increase in the number of male SZ diagnoses made after 1980s
• There is also cultural bias in the diagnosis of schizophrenia, as African Americans are far more likely to be diagnosed with SZ compared to patients belonging to Western cultures
• Genetic basis of schizophrenia

  Schizophrenia runs in families, and the concordance rates are higher for more genetically similar family members
• Schizophrenia is a polygenic disorder, meaning it has multiple contributing candidate genes
• Dopamine hypothesis


  Hyperdopaminergia (abnormally high dopamine levels) in the subcortex is responsible for positive symptoms, whereas hypodopaminergeria (abnormally low dopamine levels) in the cortex is more likely to be responsible for negative symptoms

  
• The modern understanding is that both hyper- and hypodopaminergia in different areas of the brain contribute to the development of schizophrenia
• Neural correlates


  Specific patterns of cortical activity or neural structures which coincide with specific psychological symptoms, and so are assumed to contribute towards those symptoms
• There is evidence supporting the biological and genetic basis of schizophrenia, such as the increased risk of having offspring with schizophrenia if the father is over 50 years old
• The evidence for the dopamine hypothesis is mixed, with some support from antipsychotic drugs alleviating symptoms, but also criticism that it oversimplifies the biological explanations for schizophrenia
• Antipsychotics


  Act as dopamine antagonists and so reduce dopamine activity by binding to complementary receptors on the post-synaptic membrane
• Antipsychotics alleviated the symptoms of schizophrenia, suggesting that dopamine has a key role in its development, in line with the predictions of the dopamine hypothesis
• Some researchers have criticised the dopamine hypothesis and biological explanations of schizophrenia as emphasising the role of dopamine too far
• The neurotransmitters glutamate and serotonin may also play a key role in schizophrenia, as evidenced by the antipsychotic Clozapine acting upon both of these substances and being more effective than other atypical antipsychotics in reducing schizophrenia symptoms
• Neural correlates as a means of explaining schizophrenia

  • Correlational evidence does not take into account the 'third variable problem'
  • Correlational research cannot be used to reliably demonstrate a 'cause and effect' relationship between two variables
• Psychological explanations for schizophrenia

  Suggest the development of schizophrenia is due to abnormal family communication styles, mixed messages, and the stress caused by high levels of expressed emotion
• Schizophrenogenic mother


  Characterised as being cold and rejecting, leading to a tense family climate lacking in honesty, which develops paranoia and anxiety in the child
• Double-bind theory


  Within a family, the child receives mixed messages from both parents about what is right or wrong, leading to the child seeing the world as unfair and confusing
• Expressed emotion


  The level and type of emotion shown towards the patient by their carer, which is often a significant source of stress for the patient
• Dysfunctional thought processes


  Abnormally-functioning thought processes which lead to unpleasant/undesirable outcomes, including metarepresentation and central control
• Metarepresentation


  The cognitive ability to differentiate between our own actions and the actions of others, allowing insight into the intentions and emotions of others, as well as maintaining a realistic/functional view of our own goals and intentions
• Central control


  The cognitive ability to carry out a deliberate action whilst suppressing an automatic response
• Dysfunctional thought processing can only offer explanations for the indirect, proximal causes of schizophrenia, and not the distal causes
• Psychological explanations do not accommodate for biological factors, which can explain the distal origins of schizophrenia
• The idea of the schizophrenogenic mother was based upon historical observations of families with schizophrenia members, which is hardly an objective and reliable indicator of the likelihood of developing schizophrenia
• Antipsychotics


  Dopamine antagonists that bind to complementary dopamine receptors on the postsynaptic membrane, preventing dopamine molecules from binding and resulting in an inhibitory effect
• Typical antipsychotics


  'First generation' antipsychotics historically prescribed to treat schizophrenia, with calming and sedative effects
• Atypical antipsychotics


  'Second generation' antipsychotics developed to add to the effectiveness of first generation medications and alleviate serious side effects