Aims To seek clues in the Vietnam study of 30 years ago that might shed light on which previous users of heroin are at special risk of relapsing and, among relapsers, to identify those likely to begin or return to injecting heroin.
Design To analyse information in military records and in two interviews given in the first 3 years after return from Vietnam to find predictors of post-Vietnam injection by soldiers who had used heroin while in Vietnam in 1970–71.
Participants A total of 374 Vietnam veterans who had used heroin while in Vietnam and had been interviewed twice since their return from Vietnam.
Measurements Post-Vietnam heroin injection was determined in either of two post-Vietnam interviews. Possible predictors came from interviews and military records and describe pre-Service and in-Vietnam status and behavior. Included are region of residence, race, antisocial behavior, type and level of drug use and association with illicit drug users. Possible post-Vietnam correlates of heroin injection were no job or school enrollment, alcohol problems, depression, absent or transient marriage, association with illicit drug users and other Vietnam veterans.
Findings Only a minority of those who used heroin in Vietnam had ever injected it there. Most smoked or snorted it. After their return, most of the men who had used heroin in Vietnam used it very occasionally or not at all. Among those who did use heroin more than five times after their return, most had tried injecting it. Significant predictors of post-Vietnam injection included living on the east or west coast, deviant behavior both before and in Vietnam, opiate use before Vietnam, serious involvement with heroin in Vietnam, use of non-opiate drugs before and in Vietnam, and associating with drug users before Service. The variables that increased significantly the probability of injection among men who relapsed to heroin use after return to the United States were living on the east or west coast and having a history of using non-opiate illegal drugs before they entered Service. Blacks who returned to heroin use after return were less likely to inject than were non-blacks.
Conclusions These results suggest that a high-risk group for intervention to prevent future injection would consist of people with a history of past heroin use who are currently either in remission or using without injection and who reside on either coast, have a history of antisocial behavior and have used a variety of illicit drugs other than heroin.