[1] Kings Coll London, Inst Psychiat Psychol & Neurosci, Hlth Serv & Populat Res Dept, Crespigny Pk, London SE5 8AF, England
[2] UCL, Div Psychiat, London, England
[3] Univ Calif San Diego, Dept Psychiat, La Jolla, CA 92093 USA
[4] Univ Oxford, Dept Psychiat, Oxford, England
[5] UCL, Dept Primary Care & Populat Hlth, London, England
[6] Macquarie Univ, Ctr Emot Hlth, Dept Psychol, N Ryde, NSW, Australia