Cost-effectiveness of twice-weekly versus once-weekly sessions of cognitive–behavioural therapy and interpersonal psychotherapy for depression at 12 months after start of treatment: randomised controlled trial
Department of Clinical Psychology and Psychotherapy, University of Freiburg, Germany; and Department of Clinical Psychology, Utrecht University, The Netherlands
Mohamed El Alili
Department of Health Sciences, Faculty of Science, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, The Netherlands
Steven D. Hollon
Department of Psychology, Vanderbilt University, Tennessee, USA
Frenk P. M. L. Peeters
Department of Clinical Psychological Science, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands
Arnoud Arntz
Department of Clinical Psychology, University of Amsterdam, The Netherlands
Department of Clinical Psychology, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, The Netherlands
Lotte H. J. M. Lemmens
Department of Clinical Psychological Science, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands
Pieter Dingemanse
Division of Affective Disorders, Mental Health Care Altrecht, The Netherlands
Linda Willems
Department of Mood Disorders, GGZ Oost-Brabant, The Netherlands
Patricia van Oppen
Department of Research and Innovation, GGZ InGeest Specialized Mental Health Care, The Netherlands; and Department of Psychiatry, Amsterdam University Medical Centers, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, The Netherlands
Depression Expertise Centre, Pro Persona Mental Health Care, The Netherlands; and Behavioral Science Institute, Radboud University, The Netherlands
Jos W. R. Twisk
Department of Epidemiology and Biostatistics, Amsterdam University Medical Centers, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, The Netherlands
Marcus J. H. Huibers
Department of Clinical Psychology and Psychotherapy, University of Freiburg, Germany; and Department of Clinical Psychology, Utrecht University, The Netherlands
Background Cost-effective treatments are needed to reduce the burden of depression. One way to improve the cost-effectiveness of psychotherapy might be to increase session frequency, but keep the total number of sessions constant. Aim To evaluate the cost-effectiveness of twice-weekly compared with once-weekly psychotherapy sessions after 12 months, from a societal perspective. Method An economic evaluation was conducted alongside a randomised controlled trial comparing twice-weekly versus once-weekly sessions of psychotherapy (cognitive–behavioural therapy or interpersonal psychotherapy) for depression. Missing data were handled by multiple imputation. Statistical uncertainty was estimated with bootstrapping and presented with cost-effectiveness acceptability curves. Results Differences between the two groups in depressive symptoms, physical and social functioning, and quality-adjusted life-years (QALY) at 12-month follow-up were small and not statistically significant. Total societal costs in the twice-weekly session group were higher, albeit not statistically significantly so, than in the once-weekly session group (mean difference €2065, 95% CI −686 to 5146). The probability that twice-weekly sessions are cost-effective compared with once-weekly sessions was 0.40 at a ceiling ratio of €1000 per point improvement in Beck Depression Inventory-II score, 0.32 at a ceiling ratio of €50 000 per QALY gained, 0.23 at a ceiling ratio of €1000 per point improvement in physical functioning score and 0.62 at a ceiling ratio of €1000 per point improvement in social functioning score. Conclusions Based on the current results, twice-weekly sessions of psychotherapy for depression are not cost-effective over the long term compared with once-weekly sessions.
