Response and Remission in Care-as-Usual, Waiting Lists and Pill Placebo Conditions in Psychotherapy Trials for Depression: A Meta-Analysis

Abstract

Background: It is not known how many people with depression respond and remit without treatment. Control conditions in psychotherapy trials, including care-as-usual (CAU) and waiting lists, may generate estimates of response and remission. Methods: We selected trials comparing psychotherapies with control conditions from a large database of trials and extracted response (50% symptoms reduction) and remission (HAMD < 7) rates from these conditions. Response and remission rates were pooled in a meta-analysis using random-effects models. Findings: 264 studies were included with 12,790 participants in control conditions. The mean response rates at 2 (± 1) months after baseline were 0.18 (95% CI: 0.16~0.20) for waiting lists, 0.19 (95% CI: 0.17~0.22) for CAU and 0.29 (95% CI: 0.22~0.38) for pill placebo. Remission rates were 0.11, 0.15 and 0.18, respectively. At 6 to 12 months, response and remission rates increased for waiting lists (0.32, 95% CI:0.26~0.38 and 0.29, 95% CI:0.21~0.39, respectively) and for CAU (0.23; 95% CI: 0.18~0.29 and 0.17, 95%CI: 0.09~0.28, respectively). Response and remission did not differ by the setting where CAU was delivered (specialized mental health care, primary care, general medical care, perinatal care, no treatment). No indication was found that response and remission changed by year of publication. Heterogeneity was high in almost all analyses. Interpretation: More than 75% of patients in CAU and waiting lists do not respond or remit within one to three months. CAU has not improved over time suggesting that evidence-based interventions may not have been implemented. Funding Statement: No funding was received for this study. Declaration of Interests: TAF reports grants and personal fees from Mitsubishi-Tanabe, personal fees from MSD, personal fees from Shionogi, outside the submitted work. In addition, TAF has a patent 2018-177688 concerning smartphone CBT apps pending and intellectual properties for Kokoro-app licensed to Tanabe-Mitsubishi. HN reported personal fees from Boehringer Ingelheim, Kyowa Kirin, ASKA Pharmaceutical, and Toyota Motor Corporation outside the submitted work. The other authors declare no competing interests.