Support groups (SG) for family caregivers are an intervention frequently used by associations and institutions. But their extensive use does not correspond to the current scientific interest in them. The aim of this paper is to make a historical review of the use and study of SGs for family caregivers of Alzheimer patients, describing their main features and variations, with special emphasis on data about their efficacy. In this analysis, three stages were differentiated: an initial stage (late 1970s - 1985) with studies based on subjective impressions and questionnaires showing high satisfaction among caregivers; a second stage (1985-1995) with more rigorous methodology, which led to doubts about SGs' efficacy; and a third stage (1995 - present) in which qualitative methodology focused on group process has led to renewed interest. At the end some proposals regarding the future of research on caregiver SGs are discussed.