Does therapy produce lasting personality changes?
In the last few decades, for a variety of reasons, psychotherapy research has focused primarily on symptom reduction and remission of psychiatric diagnoses. Yet throughout its history, the field has also sought to address underlying personality issues, raising an enduring question: Is lasting personal change one of the benefits of therapy?In other words, when people "graduate" from psychotherapy, they are often feeling better, but have they undergone a deeper transformation that endures after treatment ends? A 2026 study of more than 1,200 patients who completed psychodynamic psychotherapy adds to the body of evidence suggesting that the answer is yes. The study also offers clues about how such change occurs. Researchers at the University of Heidelberg found that improvements in personality functioning generally remained stable through a one-year follow-up period after therapy had ended. Patients who showed average levels of improvement during treatment tended to maintain those gains over time. Interestingly, individuals who appeared to improve less during therapy often showed greater gains after treatment, whereas those who made exceptionally large gains during therapy experienced slight declines during follow-up, although they remained improved overall. Using machine learning techniques to identify predictors of long-term change, the researchers found that improvements in interpersonal problems, such as excessive dependence on others and reduced social engagement, were associated with better outcomes. They also found that longer courses of therapy predicted greater improvements in personality functioning after treatment ended. The authors concluded that relationship-related factors play a central role in lasting therapeutic change. Their findings suggest that individual psychotherapy can help people develop healthier ways of relating to others and that these changes may continue to shape personal growth long after therapy has ended.
Citation:
I. Dönnhoff, D. Kindermann, S. Stahl-Toyota, J. Nowak, M. Orth, H. C. Friederich & C. Nikendei (26 Feb 2026): Changes in personality functioning following psychotherapy: Utilizing machine learning to identify predictors in a psychodynamic psychotherapy sample, Psychotherapy Research, DOI: 10.1080/10503307.2026.2621740