[1] Univ Stellenbosch, Dept Psychiat, MRC Unit Anxiety & Stress Disorders, ZA-7505 Tygerberg, South Africa
[2] Univ Stellenbosch, Dept Stat & Actuarial Sci, Ctr Stat Consultat, ZA-7602 Matieland, South Africa
[3] Univ Utrecht, Dept Psychol, NL-3584 CS Utrecht, Netherlands
[4] Univ Cape Town, J Block Groote Schuur Hosp, Dept Psychiat & Mental Hlth, ZA-7925 Observatory, South Africa