[1] Queen Mary Univ London, Barts & London Med Sch, Wolfson Inst Prevent Med, Ctr Psychiat,Forens Psychiat Res Unit, London EC1A 7BE, England
[2] Kings Coll London, Inst Psychiat, London WC2R 2LS, England
[3] UCL, Dept Mental Hlth, London, England
[4] Univ Leicester, Dept Psychiat, Leicester, Leics, England
[5] Drugs Anal & Res Programme, London, England