Schizophrenia: Symptoms + Prevalence
Overview:
- Affects 24 million people globally
- Treatable, not curable - treatment most effective in initial stages
- Care provided at community level
- Classed as a manic disorder until 19th century
- Typically begins in early adulthood (late teens-late 20s), slightly older in women than men
- Men affected more frequently, severely, earlier than women
- Disease persists in population despite schizophrenic people not having children
- Representation + prevalence is similar globally
Symptoms
Hallucination:
- A sensory perception experienced in the absence of external stimuli
- NOT illusions - Misinterpretations of external stimuli
- Auditory hallucinations
- Visual hallucinations
- Somatic sensations (e.g. something inside body)
DSM-5 + DSM-IV
Positive symptoms:
(Additional to expectations in good mental health)
Negative symptoms:
(Reductions to expectations in good mental health)
- Hallucinations
- Delusions
- Thought disorder
- Disorganised/catatonic behaviour
-E.g. Disorganised speech
- Blunted/flattened affect (emotional expression)
- Alogia (Lack of speech)
- Avolition (passive, lack volition)
More prominent in early stages of schizophrenia
More noticeable + severe as person ages
DSM-5 Diagnostic Criteria:
- Characteristic symptoms
- Must have 2/more delusions, hallucinations, disorganised speech
- Marked social/occupational dysfunction
- Duration of at least 6 months
- Ensure other disorder not causing behaviour
- E.g. Mood disorder, substance/medicine
- Relationship to a pervasive Developmental Disorder
Subtypes
Positive Syndrome:
Predominantly positive symptoms
Negative Syndrome:
Predominantly negative symptoms
Acute:
Have psychotic episodes + recover
Chronic:
Permanent condition
Delusion:
- False belief based on incorrect inference about external reality
- Firmly sustained despite what almost everyone else believes/obvious proof to contrary
- Belief not ordinarily accepted by other members of person's culture/subculture
Disorganised speech:
Persistent underlying disturbance of conscious thought including:
- Pressure of speech - Speaking incessantly + quickly
- Derailment/flight of ideas - switching topics inappropriately
- Thought blocking - Ideas suddenly freeze
Paranoid delusions:
- AKA delusions of persecution
- Believing people are doing things to harm you in some way when there's no external evidence for it
Delusions of reference:
- Believing things in environment are directed at you when they're not
- E.g. Believing special message being communicated to you on TV
Somatic delusions:
- False beliefs about your body
- E.g. Believing something foreign is in body
Delusions of grandeur:
- Believing you're very special/have special abilities
- E.g. Believing you're a saint
Kirkbride et al (2012): Annual incidence of psychosis in UK:
- All psychosis = 32 per 100,000
- Schizophrenia = 15 per 100,000
- Higher incidence for men + black + minority ethnic groups
- Rate varied with social disadvantage
- Affective psychoses = 12 per 100,000
DSM-IV subtypes:
(Abandoned due to unreliable diagnoses)
Paranoid, Disorganised, Catatonic, Undifferentiated, Residual
- Average lifetime risk = 1%
- Annual incidence = 0.1 or 0.2 per 1,000
- Prevalence rate = 3 per 1,000 (Oxford Textbook of Medicine)