A number of recent studies have reported on the presence and significance of clinical depression in narcotic addicts.1-7 The majority of these prior reports have been conducted with male addicts at one point in time only. To our knowledge there have been no long-term follow-up studies of narcotic addicts which have looked at the recurrence of depression. The purpose of this article is to describe the recurrence of depression during a 5-year period of follow-up of male and female narcotic addicts. It has been observed that addiction, especially chronic, and withdrawal can cause or are associated with many of the somatic and psychological symptoms of depression. To investigate this effect, episodes of depression in the present study were categorized by subjects' reports into drug-related and nondrug-related episodes, and the usefulness of this categorization in predicting future episodes of depression during the follow-up period was investigated. Incidence rates of depression in subjects without a prior history of depression are also reported.