While studies of cannabis use are numerous, the voices of consumers of cannabis are rarely heard. Even less prevalent are the voices of young people living with a mental illness, whose perceptions, attitudes and experiences are crucial to construction of effective health strategies and campaigns. This paper seeks to enhance understanding of the perceived and experienced links between cannabis use and mental health by young adults between the ages of 18 and 30 years who are living with a mental illness. With reference to insights gained from focus groups comprising members of this cohort, motivations for use and non-use of cannabis are discussed. Reappraisal of cannabis from a relatively safe and ‘soft’ drug to one that is implicated in psychosis and mental illness renders the experience of this cohort particularly relevant to public policy and debate. To the extent that cannabis can precipitate a predisposition to mental illness—thus catalysing a risk factor that may not be known in advance—it is vital that we know more about the perceptions of young people who are already confronting mental illness and their attitudes to cannabis use. Such knowledge can potentially lead both to more effective health promotion campaigns in relation to this cohort, and more effective engagement of young people in general (where, in the context of cannabis use and mental health, youth itself is a risk factor).