Applicable to: England
Several studies of cannabis use among the co-morbid treatment population recently reported high levels of cannabis use among the treatment population. A study undertaken in an inner city area of England found that ten per cent of the patients within local mental health services were misusing cannabis (Graham and Maslin 2002). Another study in an outer London borough found that 23 per cent and 34 per cent of patients attending community mental health teams and inpatient services respectively had used cannabis in the last year (Strathdee et al. 2002). Finally, another study in three inner-London psychiatric units found that around 20 per cent of the patients were regular cannabis smokers (Phillips and Johnson 2003).

References
Graham, H.L. and Maslin, J. (2002). Problematic cannabis use amongst those with severe mental health problems in an inner city area of the UK. Addictive Behaviors. 27, 261-307.

Phillips, P. and Johnson, S. (2003). Drug and alcohol misuse among in-patients with psychotic illnesses in three inner-London psychiatric units. Psychiatric Bulletin. 27, 217-220.

Strathdee, G., Manning, V., Best, D., Keaney, F., Bhui, K., Witton, J. et al. (2002a). Dual diagnosis in a Primary Care Group. Institute of Psychiatry.

Related glossary entries
Co-morbidity guidance for Scotland
Co-morbidity - All Parliamentary Committee on Drugs' findings
Hospital admissions related to mental and behavioural disorders due to cannabis