An overview of the rating scale literature reveals that the clinician now has many validated rating scales to choose from to assess his patient's condition. In general terms, it is the observer-rating scales that should be used as the principal outcome criterion in depressive disorders, both in general practice and in drug-related trials. However, self-rating scales can provide important additional information for therapy evaluation. They also provide a measure of the patient's perception of his own illness and recovery, which is not possible with observer ratings. Self-rating scales are designed for frequent use and to be sensitive to the change brought about by therapy and its time course. Observer ratings can also show sensitivity for change, and these compare well with the self-rating measures. The multimethod approach, including both observer- and self-rating scales, and covering different domains such as psychopathological symptoms, social functioning, etc. , is the preferred method for assessing patients. Using this approach, clinicians are able to build up complete profiles of their patients' illnesses and make full assessments of the efficacy of treatment and their return to normal social functioning.