Objectives: There is a view that antipsychotic drugs can be successfully withdrawn from people with intellectual disabilities with resultant health gain. This study critically examines whether antipsychotic drug withdrawal is beneficial.

Methods: 119 adults with intellectual disabilities were included in a programme of antipsychotic drug withdrawal.

Results: The clinical outcomes of this programme are poor. Only 7.6% completely withdrew from antipsychotic drugs, and 48.7% experienced onset/deterioration in problem behaviours or mental ill-health. Significant drug side effects with the introduction of new drugs were experienced by 23.3%. Resultant mean antipsychotic drug doses were higher compared with those at the start of the programme. The cost to the intellectual disabilities psychiatric service (over and above that of routine psychiatric care) was £258,050 (€391,693), and the human cost was considered high. Primary care, social care and family costs were not calculated. The only specific factors found to be associated with poor outcome were increased severity of intellectual disabilities and female gender.

Conclusions: The successful role of antipsychotic drugs in the management of problem behaviours in people who do not have verbal communication skills may relate to the pathoplastic effect of intellectual disabilities on clinical presentation, with problem behaviours being markers of eg. psychosis and anxiety disorders. Our original findings challenge the view that routine withdrawal of antipsychotic drugs is good practice; we reinterpret the existing literature, and recommend caution and vigilance in pharmacotherapy.