Classification and Diagnosis of Schizophrenia
SZ is a psychotic disorder characterised by the loss of contact with reality. It involves profound disruption of cognition and emotion but symptoms may come and go.
Under the DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders): SZ diagnosis requires at least one month duration of 2 or more positive symptoms.
- Onset normally between mid-teens and early 30s.
- Onset for women is 5-10 years later then for men: no adequate explanation for this.
- Affects 1% of the UK population
- Distortion of normal function
Delusions (bizarre beliefs, sometimes paranoid); hallucinations (auditory, visual and tactile); experiences of control (e.g. under the control of an alien force); disordered thinking (e.g. thought insertion or broadcasting).
- Lack of normal function
Affective flattening (lack of emotion); alogia (poverty of speech); avolition (loss of ability to initiate action or goal-directed behaviour).
Issues of Reliability and Validity
Reliability – can scientists agree on who has it…