[1] Karolinska Inst, Karolinska Univ Hosp Huddinge, Dept Clin Neurosci, Ctr Psychiat Res, SE-14186 Stockholm, Sweden
[2] Uppsala Univ, Dept Psychol, Uppsala, Sweden
[3] Sabbatsbergs Hosp, Dept Gastroenterol, S-11382 Stockholm, Sweden
[4] Linkoping Univ, Dept Behav Sci & Learning, Swedish Inst Disabil Res, Linkoping, Sweden