Aims: This study aimed to explore the attitudes of staff working within mental health settings toward cannabis in general and cannabis use in individuals with severe mental-health problems. Method: Twenty members of staff working within community mental health teams in Birmingham, UK, were interviewed using qualitative research methods. The overarching themes within the staff accounts are described and the interrelationship between themes explored. Findings: Staff use an 'individualized' approach when working with cannabis-using clients dependent on a number of key components, including the positive and negative effects of use, wider evidence base, client vulnerability, engagement, professional and personal views and harm reduction. It is suggested that any approach staff may take toward cannabis use at any one time is greatly dependent upon the above factors and these factors are highly client specific. Conclusions: The findings may help to explain why interventions aimed at reducing substance use in people with psychosis might prove less successful when targeting cannabis use.