Classification of Schizophrenia Including Symptoms

• Schizophrenia does not have a single defining characteristic - it appears to be a collection of unrelated symptoms
• There are two systems for the classification of mental disorders: ICD-11 which is used in the UK and the DSM-5 which is used in the USA - these differ slightly in their classification of schizophrenia
• In the ICD-11, two or more negative symptoms for one month or longer to be sufficient for diagnosis of schizophrenia (e.g. avolition and speech poverty) whereas in the DSM-5, one positive symptom must be present for at least one month for diagnosis (e.g. hallucinations)
• The ICD-11 also recognises subtypes of schizophrenia, e.g. paranoid schizophrenia is characterised by powerful delusions and hallucinations whereas catatonic schizophrenia involves problems with a patient's movement, e.g. may be immobile for long periods of time

  • The DSM-5 does not categories schizophrenia into subtypes
• Positive symptoms are an additional experience beyond those of ordinary existence
• Hallucinations are a positive symptom of schizophrenia

  • Unusual sensory experiences that have no basis in reality, they can affect any of the senses
  • For example, auditory hallucinations (hearing voices that are not present) or visual hallucinations (seeing objects that are not present)
• Delusions are a positive symptom of schizophrenia

  • Irrational/false beliefs that have no basis in reality, they can make people with schizophrenia behave in ways that make sense to them but may be bizarre to others
  • Delusions of persecution - a false belief you are being harassed by the government
  • Delusions of control - a false belief that you are being controlled by something external, e.g. aliens
• Negative symptoms are a loss of usual abilities and experiences
• Avolition is a negative symptom of schizophrenia

  • Severe loss of motivation to carry out everyday tasks and difficulty to begin or keep up with goal-directed activity
  • Some psychologists identified three signs of avolition: poor hygiene and grooming, lack of persistence in work or education and lack of energy
• Speech poverty is a negative symptom of schizophrenia

  • A reduction in the amount and quality of speech, this is sometimes accompanied by a delay in the sufferers' verbal responses during a conversation or lack of fluency