A number of both medical and nonmedical disciplines have expressed concern regarding the large numbers of individuals that fail to present to services, despite experiencing problems similar to those of active help-seekers. Such a concern is most pertinent in the field of substance misuse, particularly in terms of the role of injecting drug users in the spread of HIV and AIDS. This study looked at two samples of problem drug takers in London: 120 seeking help (the "agency group") and 120 not seeking help (the "non-agency group"). A number of factors were examined to distinguish the two groups, including sociodemographic profiles, drug histories, and self-reported "concern" and "need for help" in a wide variety of life areas. Data analysis highlighted the significance of "concern" and "need for help" in specified life areas.