[1] Univ N Carolina, Dept Psychiat, Chapel Hill, NC 27599 USA
[2] Norwegian Inst Publ Hlth, Div Mental Hlth, Oslo, Norway
[3] Univ Oslo, Dept Psychiat, N-0316 Oslo, Norway
[4] Norwegian Inst Publ Hlth, Div Epidemiol, Oslo, Norway
[5] Univ N Carolina, Dept Nutr, Chapel Hill, NC 27599 USA