Schizophrenia

• Schizophrenia


  Serious mental disorder characterised by a profound disruption of cognition and emotion. It is a type of psychosis because thoughts and emotions are so impaired that there is a loss of contact with reality. SZ affects around 1% of the population. The term schizophrenia does not represent one disorder but a group of disorders and the type a sufferer is diagnosed with depends on their symptoms.
• Diagnostic & Statistical Manual of Mental Disorders (DSM-V) symptoms of schizophrenia

  • Positive symptoms (excess of normal functioning)
  • Negative symptoms (loss of normal functioning)
• Positive symptoms


  Appear to represent an excess of normal functioning
• Negative symptoms


  Appear to reflect a loss of normal functions
• Positive symptoms


  • Delusions
  • Hallucinations
  • Disorganised thinking and speech
• Negative symptoms


  • Poverty of speech (Alogia)
  • Avolition
• Under DSM-V criteria, the diagnosis of schizophrenia requires two or more (positive or negative) symptoms to persist for at least six months. However, only one symptom is required if symptoms are considered to be particularly problematic.
• Gender bias is said to occur when the accuracy of a diagnosis of SZ is dependent on the gender of an individual. For example, some argue that the diagnostic criteria may be biased towards one gender rather than the other. Equally, clinicians may base their judgements on stereotypical beliefs held about gender.
• Symptom overlap is an issue where some symptoms of SZ are also found in other disorders such as depression and bipolar disorder. This makes it very difficult to accurately distinguish SZ from related disorders during diagnosis.
• Comorbidity refers to the extent to which two (or more) conditions co-occur. For example, many people diagnosed with SZ may also suffer from symptoms of depression, anxiety or substance abuse. This creates difficulties, not only in being able separate out these different conditions during diagnosis but also in deciding what treatments to advise.
• Culture bias may lead to problems with both the reliability and validity of diagnosis. This is when psychiatrists are influenced by their own culture's values and expectations when diagnosing patients. If what is seen as bizarre in one culture is not be viewed as bizarre in another, this could lead to inconsistent diagnosis.
• A major consequence of invalid or unreliable diagnosis of SZ relates to the social stigma carried by being incorrectly labelled.
• Genetic explanation


  SZ is passed on from one generation to the next through genetic inheritance. The more closely related the family member is to the person with schizophrenia, the greater their chance of developing the disorder. SZ is believed to be 'polygenic' where different combinations of genes make individuals more vulnerable.
• Evidence for genetic explanation

  • Family studies
  • Twin studies
  • Adoption studies
• Dopamine hypothesis


  The positive symptoms of schizophrenia are the result of the overactive transmission of the neurotransmitter dopamine. People with schizophrenia are thought to have abnormally high numbers of D2 receptors on receiving neurons, resulting in more dopamine binding and therefore more neurons firing.
• Those whose biological mothers had SZ

  The genetic risk was still evident even when the environmental influence of the biological mother was removed
• A 'healthy' adoptive family


  Could protect against those with a high genetic risk developing SZ, suggesting the environment does play a role in SZ onset as well
• Dopamine hypothesis


  The positive symptoms of schizophrenia are the result of the overactive transmission of the neurotransmitter dopamine
• People with schizophrenia


  • They are thought to have abnormally high numbers of D2 receptors on receiving neurons, resulting in more dopamine binding and therefore more neurons firing
  • Dopamine neurons play a key role in guiding attention, so disturbances in this process may well lead to the problems relating to attention, perception and thought found in people with schizophrenia
• Evidence to support dopamine hypothesis

  • Amphetamine drugs cause hallucinations and delusions similar to the symptoms seen in schizophrenia
  • L-dopa, a drug used to treat Parkinson's disease which also works by raising levels of dopamine, can also result in symptoms similar to the positive symptoms of schizophrenia
• Typical antipsychotic drugs


  • They are dopamine antagonists, working by reducing stimulation of neurons containing dopamine by blocking D2 receptors, and in doing so, reduce positive symptoms such as hallucinations and delusions
• Atypical antipsychotic drugs


  • They only temporarily block dopamine receptors, whilst also acting on serotonin receptors, and have been shown to be more effective than the typical antipsychotics in reducing schizophrenia symptoms
• Neural correlates


  Measurements of the structure or function of the brain that correlate with an experience (in this case schizophrenia)
• Evidence for the role of enlarged ventricles in SZ

  • Johnstone et al (1976) found that people with schizophrenia had enlarged ventricles while non-sufferers did not
  • Weyandt (2006) reported that enlarged ventricles are associated with negative symptoms only
• Cause and effect is unclear with neural correlates, as brain abnormalities could be the effect rather than the cause of SZ
• Biological explanations of schizophrenia (dopamine hypothesis, genetics and neural correlates) could be said to be determinist, suggesting SZ is a biological condition outside of conscious control
• Biological explanations could be viewed as more humane by removing blame from patients, but also as disempowering by suggesting SZ is outside of their control
• Biological explanations could be said to be reductionist by focusing solely on internal factors and ignoring environmental factors
• Double-bind theory


  Children who receive contradictory messages from their parents are more likely to develop SZ, leaving the child with an understanding of the world as confusing and dangerous, reflected in symptoms such as paranoid delusions
• Expressed Emotion (EE)


  The level of emotion expressed towards a SZ sufferer by their family (or carers), including verbal criticism, hostility, and emotional over-involvement
• Evidence to support double-bind theory

  • Berger (1965) found that people with SZ reported higher recall of double-bind statements from their mothers than people without SZ
• Evidence to support role of EE in the course of SZ

  • Tienari et al (2004) found that when the parenting style of the adoptive family was highly critical with low levels of empathy, this greatly increased the risk of SZ, but being reared in a 'healthy' adoptive family had a protective effect
• Family dysfunction theories


  • They have led to the development of family therapy to increase the patient's chance of recovery and decrease chances of relapse
• Cognitive explanations for schizophrenia

  The symptoms are the result of dysfunctional thought processing, with specific symptoms linked to disruption of specific cognitive processes
• Egocentric bias


  The tendency for sufferers to interpret external events as having personal significance to them, leading to false conclusions
• Central control


  The ability to suppress automatic responses while performing deliberate actions, which may be dysfunctional in some sufferers leading to 'derailed' and incoherent thoughts and speech
• Support for cognitive explanations

  • Sarin and Wallin (2004) found support for the idea that delusional patients showed various biases in their information processing, such as jumping to conclusions
• Cognitive explanations


  • They have helped in the development of Cognitive Behavioural Therapy for psychosis (CBTp) which has been extremely effective in treating SZ
• Psychological explanations of SZ (family dysfunction and cognitive) could be said to be less determinist than biological explanations, suggesting we have some degree of control over the disorder</b>
• Typical antipsychotic drugs


  They are dopamine antagonists that work directly on reducing the effects of dopamine by binding to dopamine receptors (particularly D2) without stimulating them, thus blocking their action and reducing the positive symptoms of schizophrenia