There has been a policy shift away from hospital to community in the services of all those with psychiatric disorders, including those with intellectual disability (ID), in the last 50 years. This has been accompanied recently by the growth of assertive outreach services, but these have not been evaluated in ID services. In a randomized controlled trial we compared assertive outreach with "standard" community care, using global assessment of function (GAF) as the primary outcome measure, and burden and quality of life as secondary measures. We recruited 30 patients, considerably less than expected; no significant differences were found between the primary and secondary outcomes in the two groups. The differences were so small that a Type II error was unlikely. Reasons for this lack of specific efficacy of the assertive approach are discussed and it is suggested that there is a blurring of the differences between standard and assertive approaches in practice.