AbstractA total of 32 mentally retarded adults currently suffering from major depression were examined for the prevalence of typical and atypical depressive symptoms. In contrast to persons with severe mental handicap, all those with mild handicap could be assessed using almost all DSM‐III‐R diagnostic criteria, A depressive syndrome with increased irritableness and psychomotor agitation was found in more cases of severe than mild handicap. Both groups revealed atypical symptoms; these were more frequent amongst the severely handicapped. The atypical symptoms were mosdy emerged or increased behaviour problems, and rarely a loss of adaptive behaviour. The onset of new behaviour problems appeared equally in both groups, whereas an increase in existing behaviour problems seems typical for severe handicapped subjects. The diagnosis of major depression in mentally retarded adults should consider these featu