[1] Univ Hosp, Dept Neurol, N-1478 Akershus, Lorenskog, Norway
[2] Norwegian Inst Publ Hlth, Div Mental Hlth, Oslo, Norway
[3] Akershus Univ Hosp, Helse Ost Hlth Serv Res Ctr, Akershus, Norway
[4] Univ Oslo, Helse Ost Hlth Serv Res Ctr, Akershus, Norway
[5] Ullevaal Univ Hosp, Dept Psychiat, Oslo, Norway
[6] Haukeland Hosp, Dept Neurol, Norwegian Multiple Sclerosis Natl Ctr, N-5021 Bergen, Norway
[7] Univ Bergen, Dept Clin Med, Bergen, Norway