Background: Previous studies have demonstrated that acceptance and commitment therapy (ACT) is effective for depression and may be useful for complex transdiagnostic clients.
Aims: To conduct a preliminary evaluation of whether ACT is feasible and effective when delivered by psychologists and non-psychologists for complex clients in a National Health Service (NHS) community mental health service for adults.
Method: Staff were trained in ACT and conducted one-to-one therapy with clients. Measures on general mental health, depression, fusion and values were given pre-therapy, post-therapy and at 3-month follow-up.
Results: Standardized measures showed significant improvements post-therapy for global mental health, depression, cognitive fusion and values post-treatment. These were partially maintained at follow-up and remained after an intent-to-treat analysis. There were no differences in outcomes between psychologists and non-psychologists.
Conclusions: ACT may be delivered effectively with limited training for complex cases in secondary care, though further research is needed.
Keywords: ACT; NHS; adult mental health; depression.