[1] Akershus Univ Hosp, Div Med, N-1478 Lorenskog, Norway
[2] Univ Oslo, Inst Basic Med Sci, Dept Behav Med, N-0316 Oslo, Norway
[3] Oslo Univ Hosp, Dept Psychiat, Oslo, Norway
[4] Akershus Univ Hosp, Clin Res Ctr, N-1478 Lorenskog, Norway
[5] Akershus Univ Hosp, Head & Neck Res Grp, N-1478 Lorenskog, Norway
[6] Mayo Clin, Dept Med, Rochester, MN USA
[7] Univ Bergen, Dept Clin Psychol, N-5020 Bergen, Norway