People with learning disabilities (LD) have a diversity of life-long conditions associated with a significant developmental intellectual impairment (IQ70) and deficits in social functioning. They include those with Down syndrome and many with cerebral palsy and autistic spectrum disorders. People with LD have high levels of mental and physical health problems. About 50 per cent of adults with LD have a major psychiatric or behaviour problem and 25 per cent have active epilepsy. In this population, both the diagnosis and treatment of these common problems may need a different approach from that in the general population. Although there are guidelines to assist practitioners in prescribing drugs for mental health problems in the general population, these are the first guidelines to address the specific issues relating to the pharmacological treatment of mental health problems in adults with LD. These guidelines were conceived by clinicians working in learning disability services and developed within the Leicestershire Partnership NHS Trust. They are based on both evidence and expert opinion to provide a consensus approach to prescribing as part of a holistic package of care. This practical handbook includes numerous tables and treatment algorithms. It will be an invaluable resource for psychiatrists, psychiatric nurses and general practitioners who treat adults with LD.