Schizophrenia

Definition | Aetiology | Pathophysiology | Risk factors | Signs and symptoms | Investigations | Management

Definition

Schizophrenia is a chronic psychiatric disorder characterised by episodes of psychosis, cognitive impairment, and emotional dysfunction. It involves disturbances in perception, thought, mood, and behaviour, often with significant social and occupational impairment.

Aetiology

  • Genetic factors: strong heritable component, with multiple risk-associated genes.
  • Neurodevelopmental factors: prenatal exposure to infections, obstetric complications.
  • Neurochemical imbalances: dysregulation of dopamine, glutamate, and serotonin systems.
  • Environmental factors: urban upbringing, childhood trauma, substance misuse.

Pathophysiology

  • Hyperactivity of the mesolimbic dopamine pathway contributes to positive symptoms (hallucinations, delusions).
  • Hypoactivity of the mesocortical dopamine pathway contributes to negative symptoms (apathy, social withdrawal).
  • Glutamate dysfunction and N-methyl-D-aspartate (NMDA) receptor abnormalities.
  • Structural brain changes, including reduced grey matter volume and enlarged ventricles.

Risk factors

  • Family history of schizophrenia or psychotic disorders.
  • Perinatal complications (e.g., hypoxia, infection, maternal malnutrition).
  • Early childhood trauma and adverse life experiences.
  • Substance misuse, particularly cannabis in adolescence.
  • Urban living and social isolation.

Signs and symptoms

  • Positive symptoms:
    • Hallucinations (auditory, visual, olfactory, tactile).
    • Delusions (paranoid, grandiose, persecutory).
    • Disorganised speech (tangentiality, word salad).
    • Disorganised or catatonic behaviour.
  • Negative symptoms:
    • Avolition (lack of motivation).
    • Alogia (poverty of speech).
    • Anhedonia (inability to experience pleasure).
    • Social withdrawal.
  • Cognitive symptoms: impaired executive function, poor attention, working memory deficits.

Investigations

  • Comprehensive psychiatric assessment: history, mental state examination.
  • Collateral history: from family or carers to assess functional decline.
  • Blood tests: FBC, U&Es, LFTs, TFTs, vitamin B12, folate, glucose to rule out organic causes.
  • Urine drug screen: to exclude substance-induced psychosis.
  • Neuroimaging (MRI/CT): if organic pathology suspected.

Management

1. Acute phase treatment:

  • Hospital admission if there is risk to self or others.
  • Antipsychotic medication initiation (oral or intramuscular).
  • Short-term benzodiazepines for agitation if required.

2. Pharmacological management:

  • Atypical antipsychotics (e.g., risperidone, olanzapine, aripiprazole) first-line.
  • Typical antipsychotics (e.g., haloperidol) if atypicals are ineffective.
  • Clozapine for treatment-resistant schizophrenia.

3. Psychological and social interventions:

  • Cognitive behavioural therapy for psychosis (CBTp).
  • Family interventions and psychoeducation.
  • Social skills training and vocational rehabilitation.

4. Long-term management and relapse prevention:

  • Long-acting injectable antipsychotics for non-adherence.
  • Monitoring for metabolic side effects of antipsychotics (weight, lipids, glucose).
  • Regular follow-up with community mental health teams.

5. Referral:

  • Community mental health team (CMHT): for ongoing support.
  • Psychiatrist: for specialist assessment and medication management.
  • Crisis team: if acute deterioration or risk of harm.
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