Mental Health and Cannabis / Care Services Improvement Partnership, February 2007
http://www.csip.org.uk/our-initiatives/mental-health/mental-health-and-cannabis.html
"For people with mental health problems, using cannabis can be very harmful – worsening symptoms, interfering with medication and increasing the likelihood of relapse.The damaging effects of cannabis may not be as obvious as the impact of other kinds of substance misuse. But, as the most widely used illegal drug in the UK, it is important to acknowledge the seriousness of those effects and to address them.
Information for patients and practitionersThe Government has produced a number of information materials to help mental health practitioners raise and discuss the subject of cannabis use with service users.The pack, called ‘How cannabis can affect people with mental health problems’, was created after consultation with users, carers and mental health professionals."