[1] Univ Bristol, Sch Med Sci, Psychopharmacol Unit, Bristol BS8 1TD, Avon, England
[2] Stapleford Ctr, London, England
[3] Avon & Western Wiltshire Mental Hlth Natl Hlth Se, Devizes, England
[4] Blackberry Hill Hosp, Bristol Specialist Drug Serv, Bristol, Avon, England
[5] Hammersmith Hosp, MRC, Ctr Clin Sci, London, England