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Schizoprenia - Coggle Diagram

- - - - hyperdopaminergia in the frontal lobe, and specifically Broca’s area which may have an excess of D2 receptors, may be responsible for the positive SZ symptom of auditory hallucinations, due to the overactivity of neurotransmission in the auditory areas of the brain.
      - Goldman Rakic et al (2004) suggested that hyperdopaminergia in the prefrontal cortex may be responsible for negative symptoms of SZ, such as speech poverty and avolition. This is because the prefrontal cortex is associated with logical thinking, so abnormally low dopamine levels in this area may impair an individual’s ability to construct grammatical sentences
      - Has been important in development of drug therapy
  - - - Juckel et al (2006) suggested that abnormally low levels of activation in the ventral striatum, when compared to healthy neurotypical controls, may be associated with the negative symptom of avolition. This is because the ventral striatum is associated with evaluating reward values, 5 predictability and risks. Therefore, low levels of activation and neurotransmission may mean that individuals cannot accurately assess the reward of having enough motivation to carry out normal day-to-day tasks, and so are therefore unable to cope with ‘normal’ life.
- - - - take away from the typical experience of sufferers, and so represents a ‘loss’ of experience e.g. speech poverty and avolition
        
        Avolition = “A subjective reduction in interests, desires and goals and a behavioural reduction of 2
        self-initiated and purposeful acts, including motivational deficits”. Therefore, avolition means the inability to cope with the normal pressures and motivations associated with everyday living and day-to-day tasks.
        
        Speech poverty = A negative symptom of schizophrenia which occurs when there is an abnormally low level of the frequency and quality of speech. A common type of speech poverty is ‘derailment’, which is thought to be caused by dysfunctions in central control (Frith et al, 1992) and so the sufferer cannot suppress the automatic associations that come with each new word or idea.
    - - enhance the typical experience of sufferers, and occur in addition to their normal experiences e.g. hallucinations and delusions.
        
        Delusions = A positive symptom of schizophrenia and are a set of beliefs with no basis in reality at
        all e.g. the sufferer may be paranoid that they are being stalked by the Royal Family. Different types of delusions include persecutory, delusions of grandeur, delusional jealousy, erotomania and
        somatic delusional disorders.
        
        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. Auditory hallucinations may involve hallucinating the voices of loved ones or the deceased and are, for
        example, thought to be caused by an excess of dopamine receptors in Broca’s area
  - - - These two systems have different requirements for the diagnosis of schizophrenia. Despite both
        requiring persistence of symptoms for at least 1 month, the DSM-V has more specific diagnostic criteria and so requires at least 2 or more of delusions, hallucinations, disorganized speech and
        catatonic behaviour, whereas the ICD-10 takes a broader approach to diagnosis
        
        LIMITATIONS OF CLASSIFICATION:
        
        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. ~ there are issues of validity in the diagnosis of SZ and attempting to differentiate its symptoms from that of other disorders
        
        Cultural bias ~ African Americans are far more likely to be diagnosed with SZ compared to patients belonging to Western cultures, due to their increased openness about admitting to certain SZ symptoms which may appear normal in their respective cultures. For example, the phenomenon of hearing voices.
        
        Gender bias ~ as suggested by Longenecker et al (2010), who could not find an explanation for the sudden increase in the number of male SZ diagnoses made after 1980s. Cotton et al (2009) suggests that because there are no differences in genetic susceptibility for men and women in terms of SZ, then gender bias must be to blame. Dispositional traits of most women, such as high interpersonal functioning and being able to work
        even when suffering, means that such traits may mask the symptoms of schizophrenia.
        
        System overlap- Two conditions share symptoms. Schizo and bipolar both share delusions (positive) and avolition (neg) could be a single condition- hard to distinguish. Sleep disturbance found in schizophrenia, depression and bipolar.
- - - - SUPPORTING EVIDENCE:
        Stirling et al (2006). The researchers found that SZ sufferers made significantly more mistakes and twice as long to complete the task, compared to a healthy neurotypical control group.
- - - - The key advantage of Clozapine is the improvements in cognitive functioning and mood which patients experience when taking it. This is particularly useful considering that SZ has a 50% comorbidity rate with depression
      - On the other hand, the key advantage of Risperidone is that smaller doses are required because it acts more strongly on dopamine receptors compared to Clozapine, and so would be particularly suited to patients who do not suffer from depression but have a previous history of blood-related illnesses.