diagnosis and classification of schizophrenia

• Reliability

  The consistency of the findings or results of a psychology research study
• Validity

  Validity refers to whether a measure actually measures what it claims to be measuring. Meaning the data collected is accurate and represents some truth compared to others outside of the study. If it does, then the test is valid.
• key term - classification of mental disorder

  the process of organising symptoms into categories based on which symptoms frequently cluster together
• key term - schizophrenia

  a severe mental disorder where contact with reality and insight are impaired, and example of psychosis
• key term - positive symptoms of schizophrenia

  
  

  atypical experiences in addition to normal experiences e.g. hallucinations & delusions
• key term - hallucinations

  positive symptom of SZ. They are sensory experiences that have either no basis in reality or are distorted perceptions of things that are there.
• key term - delusions

  positive symptom. They involve beliefs that have no basis in reality e.g., a person believes that they are someone else or that they are the victim of a conspiracy.
• key term - negative symptoms of SZ

  atypical experiences that represent the loss of a usual experience e.g., loss of clear thinking or motivation
• key term - speech poverty

  negative symptom of SZ. It involves reduced frequency and quality of speech.
• key term - avolition

  a negative symptom of SZ. It involves the loss of motivation to carry out tasks and results in lowered activity levels
• co-morbidity

  the occurrence of two disorders/conditions together e.g., a person has both SZ and a personality disorder. When two conditions are frequently diagnosed together it calls into question the validity of classifying the 2 disorders separately
• key term - symptom overlap

  occurs when two or more conditions share symptoms. Where conditions share symptoms this calls into question the validity of classifying the 2 disorders separately.
• diagnosis and classification of schizophrenia

  
  

  Diagnosis and classification are interlinked. In order to diagnose a specific disorder we need to distinguish one disorder from another. This is done by identifying clusters of symptoms that occur together and classifying this as one disorder. Diagnosis is then possible by identifying symptoms and deciding what disorder a person has.

  SZ is a collection of seemingly unrelated symptoms. There are many misconceptions and exaggerations surrounding the nature of SZ
• systems for classifications of mental disorder

  There a 2 major systems for the classification of mental disorder – the World Health Organisations international classification of disease (ICD-10 version 11 has been used since 2022) AND the American Psychiatric Associations Diagnostic and Statistical manual edition 5 (DSM-5).

  These differ slightly in their classification of schizophrenia, in DSM-5 one positive symptom must be present where as 2 or more negative symptoms must be present for a diagnosis under ICD-11
• symptoms of sz - positive

  positive symptoms are additional experiences beyond those of ordinary experience
• positive symptoms - hallucinations

  unusual sensory experiences that have no basis in reality or are a distorted perception of real things. Hallucinations can be experienced in relation to any sense. The person may for example see distorted facial expressions or occasionally people or animals that are not there.
• positive symptoms - delusions 


  also known as paranoia, delusions are irrational beliefs. They make the individual behave in ways that make sense to them but are bizarre to others. Common delusions involve being an important historical, political or religious figure such as Napolean or Jesus – delusions of grandeur. Delusions also commonly involve being persecuted, perhaps by government or aliens or of having superpowers. Another class of delusions concern the body – a person may believe they are under external control
• negative symptoms of SZ

  involve the loss of usual abilities and experiences
• negative symptoms - speech poverty

  SZ is characterised by changes in patterns of speech. Speech poverty is a negative symptom because the emphasis is on a reduction in the amount and quality of speech. May include a delay in verbal responses during conversation. Nowadays more emphasis is placed on speech disorganisation – speaker becomes incoherent or changes topic mid sentence (positive symptom in DSM-5)
• negative symptoms - avolition

  sometimes called apathy. It is a severe loss of motivation to carry out everyday tasks e.g., work, hobbies, personal care. It results in lowered activity levels and unwillingness to carry out goal-directed behaviour.