[1] Univ Southampton, Fac Med, Southampton SO9 5NH, Hants, England
[2] Univ Cape Town, Dept Psychiat & Mental Hlth, ZA-7925 Cape Town, South Africa
[3] Univ Manchester, Neurosci & Psychiat Unit, Manchester, Lancs, England
[4] Univ London Imperial Coll Sci Technol & Med, Div Expt Med, London, England
[5] Karolinska Inst, Stockholm, Sweden
[6] Univ Gottingen, Dept Psychiat & Psychotherapy, D-37073 Gottingen, Germany
[7] Univ Groningen, Univ Med Ctr Groningen, Dept Nucl Med & Mol Imaging, NL-9713 AV Groningen, Netherlands
[8] PRA Int Zuidlaren, Zuidlaren, Netherlands
[9] Cambridge & Peterborough NHS Fdn Trust, Cambridge, England
[10] Univ Toronto, Ctr Addict & Mental Hlth, Toronto, ON, Canada
[11] Univ Hertfordshire, Postgrad Med Sch, Hatfield AL10 9AB, Herts, England
[12] Anxiety UK, Manchester, Lancs, England
[13] North Bristol NHS Trust, Bristol, Avon, England
[14] Kings Coll London, Inst Psychiat, London WC2R 2LS, England
[15] OCD Act, London, England
[16] Newcastle Univ, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[17] Leiden Univ, Med Ctr, Dept Psychiat, Leiden, Netherlands
[18] Tech Univ Dresden, Inst Clin Psychol & Psychotherapy, D-01062 Dresden, Germany