The influence of patient variables on polypharmacy and combined high dose of antipsychotic drugs prescribed for in-patients

Aims and Method A1-day census, involving 3576 psychiatric in-patients prescribed antipsychotic medication, was conducted as a prelude to a multi-centre audit. The aim was to explore the extent to which a number of patient variables explain antipsychotic polypharmacy and the use of high doses of these drugs. Results Prescriptions of more than one type of antipsychotic drug were made for 50.5% of patients. Patient factors that influenced the probability of polypharmacy were: younger age, being male, detained under the Mental Health Act and on a rehabilitation or forensic ward, and a diagnosis of schizophrenia. The effect of ethnicity was not significant. Polypharmacy was the most powerful factor influencing the probability of being prescribed a high dose. Identified patient variables accounted for only 18% of the variance in dose prescribed. Clinical Implications The patient and clinician factors that account for the unexplained variance need to be identified.