[1] Kings Coll London, Inst Psychiat, London SE5 8AF, England
[2] Univ Cambridge, Dept Psychiat, Cambridge CB2 1TN, England
[3] Natl Inst Hlth Res Biomed Res Ctr Mental Hlth, London, England
[4] Univ Westminster, Dept Psychol, London W1R 8AL, England
[5] Univ W Indies, Fac Med Sci, Psychiat Unit, St Augustine, Trinidad Tobago
[6] Univ Nottingham, Div Psychiat, Nottingham NG7 2RD, England