Drug-free patients should be on separate psychiatric wards from those suffering from cannabis-induced psychosis, a leading mental health charity has stated.

Marjorie Wallace, chief executive of Sane, said it was sometimes unsafe for suicidal patients who did not take drugs to stay in psychiatric wards filled with "aggressive" drug users.

She said: "Psychiatrists are saying they are having to take huge risks with people they know are suicidal but cannot advise them to come onto the wards because it would be worse for them. They would be exposed to aggression."

Charity DrugScope supported the idea of separate wards for people with drugs and mental health problems so they could get therapy tailored to their needs.