[1] Natl HealthCare Grp, 10 Buangkok View,Buangkok Green Med Pk, Singapore 539747, Singapore
[2] Inst Mental Hlth Singapore, Dept Community Psychiat, Singapore, Singapore
[3] Natl Univ HealthCare Syst, Dept Psychol Med, Singapore, Singapore
[4] Singapore Gen Hosp, Dept Psychiat, Singapore, Singapore
[5] Inst Mental Hlth, Natl Addict Management Serv, Singapore, Singapore