Exploring the effect of psychotherapy and comorbidity on the course of depression and personality disorders

Introduction This thesis is an explorative study to the effect of psychotherapy and comorbidity on the course of depression and personality disorders. Therefore it looks at five outcome studies and addresses the following topics: the effectiveness and sustained effect of short-term treatment for depression and the effect of comorbid personality disorders and other clinical characteristics on depression outcome. Furthermore, we will reflect on the effectiveness of short-term and long-term schema group therapy for patients with PD and the impact of comorbid depression and other clinical variables on treatment outcome in patients with PD. The final study to be discussed here looks at the effectiveness and cost-effectiveness of mentalisation-based day treatment for patients with BPD. In all the studies, the patients were recruited from different specialised outpatient mental health clinics in a large city in the Netherlands. Discussion Short-term psychotherapy with a focus on MDD and PD is effective regardless of the presence of comorbid PD and high levels of depression severity respectively. Comorbidities should not therefore preclude referral to psychotherapy with an exclusive focus on MDD or PD. Although our study in Chapter 3 found that comorbid PD had a negative effect on depression outcome,the literature on this topic is inconclusive. Furthermore, PD patients with severe depressive symptoms or psychological distress who were allocated to short-term schema group therapy first seem to need more time to reach the threshold of remission. However, improvement seems to continue after treatment termination and so a treatment break could be advisable . In the treatment of borderline personality disorders, the results of our effectiveness/ cost-effectiveness study are in line with the results of other studies comparing specialised intensive treatment and less intensive structural treatment manuals. These findings justify the use of less intensive treatment, and a well-structured outpatient treatment format, which further patient turnover, shorten waiting lists and increase the dissemination and access to treatment for these severe patients. However, many patients do not achieve remission and all the studies clearly indicate that there is room for improvement. Clinical implications and future research Short-term psychotherapy is effective for a broad group of depressed patients (with or without comorbid PD). Adding pharmacotherapy improves the effect but the effect may not be sustained in the very long term. Clinicians should be alert to not only the presence of a comorbid PD but also residual depressive symptoms after treatment, baseline symptom severity and interpersonal functioning, which may be important as negative predictors and which therefore need to be taken into account when evaluating the treatment plan with the patient.Further research into the differential effects of these factors is required. For PD patients with or without severe depressive symptoms, short-term therapy in groups may be a valuable first step in a stepped-care programme. It may be advisable to include a break in treatment for patients who have not achieved remission at treatment termination. After a break, new or extended treatment options in non-remitted patients could be clinically useful and necessary. However, evidence about what non-remitted patients require after short-term treatment is still very scarce. Future research into time-limited treatment options should therefore focus on follow-up interventions. In the treatment of patients with BPD, the initiation of structured and supportive outpatient psychotherapy over a period of between one and two years is indicated. A treatment programme of this kind is less intensive and stressful for the patient. However, many patients do not achieve remission and all studies clearly indicate that there is room for improvement. Future studies could therefore evaluate whether more intense or longer treatment programmes are effective/cost-effective for specific subgroups of patients.