Background: Posttraumatic embitterment disorder (PTED) is a reaction to unjust or humiliating life events, including embitterment and impairment of mood, somatoform complaints, reduction in drive, withdrawal from social contacts, and even suicide and murder suicide. Patients have been shown to be nonresponders to many treatments. This paper gives an outline of cognitive behaviour therapy based on wisdom psychology and reports first data on treatment effects. Method: In a first pilot study on psychotherapy for PTED, a cohort of 25 PTED inpatients was treated with routine multidimensional cognitive behaviour therapy. A second consecutive cohort of 28 patients was treated with PTED-specific cognitive behaviour therapy, which is based on wisdom psychology (wisdom psychotherapy) and another 29 patients with cognitive behaviour therapy based on wisdom psychology together with additional hedonia strategies (wisdom and hedonia psychotherapy). Treatment integrity was measured with special modules of the Behaviour Therapy Competency Checklist. The outcomes were measured in all 3 groups with the SCL-90 and a global clinical rating of patients and therapists on treatment outcome. Results: There were significant and clinically meaningful reductions in the SCL score after wisdom therapy, as compared to routine treatment. In clinical ratings by therapists and patients, both specific treatments were judged as more effective than treatment as usual. Additional hedonia strategies did not lead to better treatment effects. Conclusions: The results of this pilot study suggest that wisdom psychology offers an approach to treat PTED and justify further randomized controlled outcome studies.