Characterization, Treatment, and Long-term Follow-up of Fatigued Patients in Primary Care

Inclusion Criteria: 1. age 18-67 2. enrollment at a primary care clinic in Region Stockholm 3. severe, functionally disabling fatigue as a central symptom for at least 3 months 4. The fatigue has an identifiable start and hence has not been life-long; 5. The fatigue is not a direct effect of an active disease process motivating another treatment (e.g., hypo-/hyperthyroidism, anemia, cancer, dementia) or the effect of medication 6. regular access to a computer and to the Internet 7. ability to read and write in Swedish. 8. ability to visit a study center for participation in potential assessments and treatment sessions (maximum 60 minutes) and to take part of written material via the internet. Exclusion Criteria: 1. substance abuse disorder in the past 6 months 2. Current or past psychosis or bipolar disorder 3. Primary psychiatric disorder of such severity that it merits evidence-based treatment (e.g., obsessive compulsive disorder, moderate to severe depression, post-traumatic stress disorder, anorexia nervosa) 4. elevated risk for suicide 5. deliberate self harm in the past 6-months (e.g., cutting, burning, poisoning); 6. BMI\>40 7. Initiated or changed psychopharmacological medication (e.g., for depression or anxiety disorders) in the past month 8. ongoing chemotherapy 9. intellectual disability (e.g., severe autism) that affects ability to work with the treatment 10. pregnancy 11. life circumstances that complicate or make treatment impossible (e.g., domestic violence, ongoing legal disputes, disputes with social insurance agency, planed or on-going work capacity assesment regarding permanent work disability pension or planed surgery) 12. ongoing psychological treatment and/or multimodal rehabilitation. 13. working night shifts