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:

  1. Characteristic symptoms
  • Must have 2/more delusions, hallucinations, disorganised speech
  1. Marked social/occupational dysfunction
  2. Duration of at least 6 months
  3. Ensure other disorder not causing behaviour
  • E.g. Mood disorder, substance/medicine
  1. 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)