Over the past 50 years the relationship between alcoholism and psychiatric disorders, such as depression, anxiety and schizophrenia, has been the subject of a great deal of research. Psychiatric problems have been seen as both a cause and a result of alcoholism. Whatever the relation between alcoholism and psychiatric disorder is, it may have significance for the development of differentially effective treatment strategies. Several authors have argued that the presence and nature of psychiatric symptoms should form the basis of a classification system for alcoholics. Given the potential rewards of such a system for both understanding the aetiology of alcoholism and developing effective treatment strategies, it is important to have a clear picture of the nature and extent of this relationship. This paper reviews critically the published studies of the association between alcoholism and psychiatric disorder and outlines directions for future research.