[1] Univ Cantabria, Marques Valdecilla Univ Hosp, Clin & Social Psychiat Res Unit, Santander 39008, Spain
[2] Univ Liverpool, Dept Primary Care, Liverpool L69 3BX, Merseyside, England
[3] Mental Hlth Res Grp, Turku, Finland
[4] Dept Gen Practice & Community Med, Oslo, Norway
[5] Univ Coll Dublin, Mater Hosp, Dublin 2, Ireland
[6] Cardiff Univ, Div Gen Practice, Wrexham, Wales
[7] Clin & Social Psychiat Res Unit, Santander, Spain
[8] Univ Liverpool, Dept Primary Care, Liverpool L69 3BX, Merseyside, England
[9] Univ Manchester, Sch Epidemiol & Hlth Sci, Manchester M13 9PL, Lancs, England
[10] Univ Liverpool, Dept Psychiat, Liverpool L69 3BX, Merseyside, England