Inclusion Criteria:  Living in Sweden Access to the internet Completed pre-treatment assessment If on psychotropic medication, dose kept stable for at least 4 weeks before randomization and the participant agrees to keep it constant during treatment  Exclusion Criteria:  Severe depression (≥ 30 on the Montgomery Åsberg Depression Rating Scale-Self Rated [MADRS-S] at screening) Suicidal ideation (≥ 4 on the suicide item of the MADRS-S at screening), Psychosis Alcohol or substance use disorder as primary diagnosis or likely to severely interfere with treatment Ongoing psychological treatment Pregnancy (>29 wk gestation) Another somatic condition that requires immediate treatment and/or is deemed to be the primary condition Insufficient knowledge of the Swedish language or insufficient computer skills to benefit from the text-based online treatment.