[1] Univ North Dakota, Dept Psychol, Grand Forks, ND 58202 USA
[2] Univ N Carolina, Dept Psychiat, 101 Manning Dr,CB 7160, Chapel Hill, NC 27515 USA
[3] Univ N Carolina, Dept Neurosurg, Chapel Hill, NC 27515 USA
[4] Univ N Carolina, Dept Nutr, Chapel Hill, NC 27515 USA
[5] Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden
[6] Curtin Univ, Sch Psychol, Perth, WA, Australia
[7] Univ Western Australia, Sch Paediat & Child Hlth, Perth, WA, Australia