Acute psychosis

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

Definition

Acute psychosis is a severe mental state characterised by a loss of contact with reality, often including hallucinations, delusions, disorganised thinking, and behavioural disturbances.

Aetiology

  • Primary psychiatric causes:
    • Schizophrenia.
    • Bipolar disorder (mania with psychotic features).
    • Severe depression with psychotic features.
    • Schizoaffective disorder.
  • Secondary causes:
    • Substance-induced psychosis (e.g., cannabis, cocaine, amphetamines, alcohol withdrawal).
    • Neurological disorders (e.g., epilepsy, brain tumours, neurodegenerative diseases).
    • Metabolic imbalances (e.g., hypoglycaemia, hypercalcaemia).
    • Infections (e.g., encephalitis, HIV, syphilis).

Pathophysiology

  • Disruption of dopaminergic pathways, particularly hyperactivity in the mesolimbic system.
  • Glutamatergic dysfunction implicated in schizophrenia and other psychotic disorders.
  • Serotonin dysregulation contributing to perceptual disturbances and hallucinations.
  • Inflammatory and neurodevelopmental factors may also play a role.

Risk factors

  • Family history of psychotic disorders.
  • Substance misuse.
  • Psychosocial stress or trauma.
  • Sleep deprivation.
  • Underlying neurological conditions.
  • History of childhood adversity.

Signs and symptoms

  • Hallucinations (auditory, visual, olfactory, or tactile).
  • Delusions (persecutory, grandiose, nihilistic).
  • Disorganised speech (tangentiality, incoherence).
  • Disorganised or catatonic behaviour.
  • Affective disturbances (blunted or inappropriate affect).
  • Lack of insight.

Investigations

  • Comprehensive psychiatric assessment: history, mental state examination.
  • Blood tests: FBC, U&Es, LFTs, TFTs, calcium, glucose, vitamin B12, folate.
  • Toxicology screen: urine drug screen for substances.
  • ECG: baseline before initiating antipsychotic treatment.
  • Brain imaging (MRI/CT): if new-onset psychosis or neurological symptoms.
  • Autoimmune/infectious screening: if suspected underlying cause (e.g., encephalitis).

Management

1. Immediate interventions:

  • Ensure safety of patient and others.
  • Consider hospital admission if risk to self or others.
  • Use de-escalation techniques and provide a low-stimulation environment.

2. Pharmacological treatment:

  • Oral atypical antipsychotics (e.g., olanzapine, risperidone, quetiapine).
  • Intramuscular lorazepam or haloperidol for acute agitation (if oral route not viable).
  • Consider long-acting injectables if recurrent psychotic episodes.

3. Psychological and social support:

  • Cognitive behavioural therapy (CBT) for psychosis.
  • Family interventions to support caregivers.
  • Social support and rehabilitation services.

4. Referral:

  • Crisis team: if patient requires urgent psychiatric intervention but not hospitalisation.
  • Community mental health team (CMHT): for long-term follow-up and care coordination.
  • Inpatient psychiatric admission: if severe risk to self or others.
PsychiatrymypanotesAcute Psychosis