Diagnosis & Classification of Schizophrenia

• Schizophrenia- Overview

  A type of psychosis, a severe mental disorder in which thoughts and emotions are so impaired that contact is lost with external reality. Most common psychotic disorder, affecting about 1.1% of the population. Most commonly diagnosed between age 15 and 35, with men being more affected than women.
• Classification of Schizophrenia

  SCZ doesn't have a single defining characteristic, it is a cluster of symptoms which appear to be unrelated. The 2 major systems for the classification of mental disorder are the ICD-10 and the DSM-5. These differ in their classification of SCZ. In DSM-5 one positive symptom is required, in the IDC-10 two or more negative symptoms are sufficient.
• Classification of Schizophrenia- ICD-10

  Recognises a range of SCZ subtypes. Paranoid SCZ- characterised by powerful delusions and hallucinations but relatively few other symptoms. Hebephrenic SCZ- involving primarily negative symptoms. Catatonic SCZ- disturbance of movement, leaving the person immobile or alternatively overactive. Previous editions of the DSM have recognised these subtypes, but these have been dropped in the DSM-5.
• Positive Symptoms of SCZ

  Atypical experiences experienced IN ADDITION to normal experiences, including hallucinations and delusions. They appear in excess.
• Positive Symptoms of SCZ- Hallucinations

  Bizarre, unreal perceptions of the environment that they can usually hear, but it can be visual, olfactory (smell), or tactile (feeling). Many report having a voice or someone telling them to do something; e.g. harm someone or criticising themselves. They may see distorted facial expressions or objects which aren't present.
• Positive Symptoms of SCZ- Delusions

  Bizarre or paranoid beliefs that are untrue, such as the belief that they are being followed/spied upon. Some delusions concern the body, people may believe a part of them is under external control. As a result, the behave in ways which make sense to them but not others. The vast majority aren't aggressive as they are more likely to be the victims than perpetrators.
• Positive Symptoms of SCZ- Disorganised Speech

  Due to abnormal thought processing, the individual has problems organising their thoughts which can be seen through their speech. They may move from topic to topic, even mid sentence.
• Positive Symptoms of SCZ- Grossly Disorganised or Catatonic Behaviour

  Inability to complete or even begin a task. Can then cause decreased hygiene or wearing inappropriate clothes. They may even remain in a rigid and unmoving position.
• Negative Symptoms of SCZ

  Atypical experiences that represent the loss of a usual experience, such as clear thinking or 'normal' levels of motivation.
• Negative Symptoms of SCZ- Alogia (Speech Poverty)

  Said to reflect the slowing or blocking of thoughts. Individuals may produce fewer words in a given time on a fluency task. They don't know less words, they just struggle to produce them. It may also show through the use of shorter phrases and less complex sentences- often associated with the long and earlier onset of the illness.
• Negative Symptoms of SCZ- Avolition

  A reduction of interest or desire and an inability to initiate or persist in goal-directed behaviour; e.g. staying inside all day doing nothing even when there are activities and social involvement outside. Andreason identified 3 signs: poor hygiene and grooming, lack of persistence in work or education, and a lack of energy.
• Negative Symptoms of SCZ- Affective Flattening

  A reduction in the range and intensity of emotional expression. Seen within facial expressions, tone, and body language.
• Negative Symptoms of SCZ- Anhedonia

  A loss of interest or pleasure in all or almost all activities.
• AO3: Diagnostic Reliability

  Meaning the diagnosis of SCZ must be repeatable; inter-rater reliability refers to the extent to which different assessors agree on their assessments. Cheniaux et al had 2 psychiatrists independently diagnose 100 people using both criteria. Inter-rater reliability was poor, one diagnosed 26 with the DSM and 44 with the ICD; and the other was 13 with DSM and 24 with the ICD. Poor reliability weakens the diagnosis of SCZ. IDA- Ethical Implications
• AO3: Validity

  The extent to which the diagnosis represents something real and distinct from other disorders. Criterion validity- do different assessment systems reach the same diagnosis. In Cheniaux et al's study it was found that SCZ was more likely to be diagnosed using the ICD. Suggesting SCZ is either over-diagnosed with the ICD, or under-diagnosed with the DSM. IDA- Ethical Implications
• AO3: Co-Morbidity

  Refers to the extent to which two (or more) conditions can co-occur; if they occur together frequently the validity is questioned. SCZ is commonly diagnosed with other conditions; Buckley et al estimates co-morbid depression occurs in 50% of patients, 47% had co-morbid substance abuse, 29% with PTSD. If depression occurred with half, in terms of diagnosis, it may be that we cannot tell the difference. In terms of classification, they may be seen as a single condition instead (SCZ may be severe depression).
• AO3: Symptom Overlap

  Despite claims that (+) and (-) symptom divide would make classification easier, many symptoms overlap with other conditions. Both SCZ and bipolar involve positive symptoms like delusions and negative symptoms like avolition. Questioning the validity of the classification and diagnosis. Ellason and Ross found people with DID actually have more SCZ symptoms than those diagnosed as schizophrenic- are they then separate disorders?
• AO3: Real-World Example

  Rosenhan's study demonstrates how diagnosis for mental health can be flawed.
• AO3: Gender Bias

  Longnecker et al did a meta-analysis of the presence of SCZ and found that since 1980s men have been diagnosed more than women (prior there was no difference). Though this could be genetic, Cotton et al states that women typically function better than men, being likely to work and have good family relationships. Their better interpersonal functioning may bias practitioners to under-diagnose SCZ as they can mask symptoms.
• AO3: Culture Bias

  African Americans and English people of Afro-Caribbean origin are several times more likely to be diagnosed than White people. Yet rates in Africa and West Indies aren't high, it isn't then a genetic vulnerability, its culture bias. Positive symptoms, like hearing voices, are more acceptable due to beliefs of communication with ancestors, thus they are more ready to acknowledge such experiences- the psychiatrist is then likely to see these as bizarre and irrational.
• AO3: Culture Bias

  Escobar found that (overwhelmingly white) psychiatrists may tend to over-interpret symptoms and distrust the honesty of Afro-Caribbeans during diagnosis.

  Suggesting poor validity as cultural beliefs and behaviours act as confounding variables, and racist distrust of Black patients.