Drugs used in psychosis & related disorders

All drugs (except clozapine) have similar antipsychotic efficacy, however the side-effect profile varies greatly; refer to Antipsychotics – relative side-effects. Select drugs on an individual basis and take into account the indication:

  • psychosis/schizophrenia – consider oral atypical antipsychotics first-line (see below). Keep the patient on a typical antipsychotic if they are stable.
  • short-term sedation – typicals can be used at a sufficiently low dose to avoid side-effects.
  • mania/hypomania – patients may be particularly sensitive to developing tardive dyskinesia, so atypical antipsychotics are considered first-line in the longer term, usually as an adjunct to a mood stabiliser. Typical antipsychotics can be used short-term and typical depots are occasionally used in the longer term where compliance has been poor.
  • bipolar depression – quetiapine is an effective treatment for bipolar depression and does not appear to be associated with a switch to mania.
  • dementia – antipsychotic medication should be reserved for severe non-cognitive symptoms or behaviour that challenges, where other approaches have failed or would be inappropriate. Refer to Psychotropics in older adults.

Introduce clozapine if schizophrenia is inadequately controlled despite the sequential use of 2 or more antipsychotics (one of which should be an atypical antipsychotic) each for at least 4 to 6 weeks.

• There is a clear increased risk of stroke and a small increased risk of death when antipsychotics (typical or atypical) are used in older people with dementia (www.gov.uk/drug-safety-update 2012).
• Antipsychotics may also have adverse effects on cognition.

MHRA advice: Clozapine and other antipsychotics: monitoring blood concentrations for toxicity (August 2020) (www.gov.uk).