Sick-listed persons are randomized twice : 1 ) to receive one of two invitations to participate in the study or not receive an invitation , where the latter `` untouched '' control group will be monitored for future sick leave in the National Social Security Register , and 2 ) after inclusion , to a Long or Short inpatient multicomponent rehabilitation program ( depending on which invitation was sent ) or an outpatient cognitive behavioral therapy group comparative program .