After a discussion of methodological issues of the past 20 years, literature on dropping out of treatment was critically reviewed in six areas: hospital treatment of general psychiatric and tubercular patients, outpatient treatment of internal medical conditions, alcoholism, heroin addiction, general psychiatric outpatient psychotherapy, and double-blind drug studies. Fifteen factors were found to predict dropping out in 100%, 83%-88%, and 60%-75% of the relevant studies: (a) social isolation and/or unaffiliation, therapist attitudes and behavior, discrepancies between patient and therapist treatment expectations; (b) passive-aggressive behavior, family attitudes and behavior, motivation, behavioral and/or perceptual dependence, psychological mindedness and/ or -denial, symptom levels and symptom relief, socioeconomic status, sociopathic features, alcoholism and/or drug dependence; (c) age, sex, and social stability.One of the most vexing problems facing the physician, whether he is a surgeon, internist, or psychiatrist, is that far too many of those entrusted to his care, both inpatients and outpatients, drop out of treatment before they have completed it to his satisfaction. Although the question of the dropout has most often engaged the attention of psychiatrists, it also crops up from time to time in papers by internists, for whom there is no reason to believe that it is any less serious a problem. Where studied, the dropout problem has usually been in the context of treating chronic conditions that require prolonged treatment. The extent of this problem can be inferred ^rom the fact that in general psychiatric clinics, 20%-57% of the patients fail to return after the first visit (Blenkner,
