Self-help groups are increasingly utilised by communities of interest and shared experience, services, and government departments as platforms for supporting and improving health and social care outcomes for drug and alcohol users. Traditional 12-step self-help groups like Narcotics Anonymous and Alcoholics Anonymous (NA and AA) are worldwide organisations and each have their own programme of change, language, criteria for membership, processes for problem resolution, and self-transformation. Within these types of groups, members are openly encouraged to identify with and adopt an (diseased) identity that is consistently invoked to work on the self. In the self-help recovery literature, it is widely recognised that individuals can benefit by thinking about themselves as “diseased” and then acting and behaving in a manner which is congruent with their reframed “identity”. Less is known about the processes involved in this and social-, psychological-, and health-related implications for individuals in drug- and alcohol-specific self-help groups. A thematic analysis of data from (n-36) in-depth qualitative interviews with long-term (6 months–10 years) self-help users identified four themes associated with the adoption of a diseased identity and self-help group processes: (1) normalising the disease and illness; (2) identifying as diseased; (3) living as a diseased individual; and (4) one addict helping another addict. The results of this research should not be interpretated as a critique of the 12-step approach or groups. Instead, it should be recognised that whilst improvements to individual wellbeing are reported, identifying as diseased can exacerbate negative self-perceptions that individuals hold about themselves, their character, capabilities, and ability. Being diseased, accepting disease, and identifying as diseased also has the potential to inhibit their engagement with wider social networks and professional services outside of their own fellowship or group. We conclude this paper by exploring the implications of a “diseased identity” and self-help processes for individuals who access self-help groups, and health and social care practitioners who support self-help users as they engage with services and self-help groups.