Depression is a prevalent and impairing condition. Behavioral activation (BA) is a parsimonious, cost-effective, and easily disseminated psychological intervention for depression. The current meta-analysis expands on the existing literature supporting the efficacy of BA for depression by examining the effects of BA on additional relevant outcomes for patients with depression, namely the reduction in anxiety symptoms and increase in activation.

Randomized controlled trials of BA for depression compared to active and inactive control were identified via a systematic review. Effect sizes using Hedges's g were calculated for each outcome compared to both active and inactive control using random effects models. Subgroup analyses were used to examine the inclusion of a discussion of values as a moderator of depression symptom outcome in BA.

Twenty-eight studies were included. Meta-analyses of symptom change between groups from baseline-to-post intervention indicated that BA outperformed inactive control conditions for improvements in depression (g = 0.83), anxiety (g = 0.37), and activation (g = 0.64). The difference between BA and active control conditions was not significant for improvements in depression (g = 0.15), anxiety (g = 0.03), and activation (g = 0.04). There was no evidence for a discussion of values augmenting BA efficacy. Study quality was generally low, and there was evidence of publication bias.

In addition to improving depression, BA shows efficacy for reducing symptoms of anxiety and increasing activation. BA may not offer better outcomes relative to other active interventions. There is room for improvement in the quality of research in this area.

It is unclear what session frequency is most effective in cognitive–behavioural therapy (CBT) and interpersonal psychotherapy (IPT) for depression.

Compare the effects of once weekly and twice weekly sessions of CBT and IPT for depression.

We conducted a multicentre randomised trial from November 2014 through December 2017. We recruited 200 adults with depression across nine specialised mental health centres in the Netherlands. This study used a 2 × 2 factorial design, randomising patients to once or twice weekly sessions of CBT or IPT over 16–24 weeks, up to a maximum of 20 sessions. Main outcome measures were depression severity, measured with the Beck Depression Inventory-II at baseline, before session 1, and 2 weeks, 1, 2, 3, 4, 5 and 6 months after start of the intervention. Intention-to-treat analyses were conducted.

Compared with patients who received weekly sessions, patients who received twice weekly sessions showed a statistically significant decrease in depressive symptoms (estimated mean difference between weekly and twice weekly sessions at month 6: 3.85 points, difference in effect size d = 0.55), lower attrition rates (n = 16 compared with n = 32) and an increased rate of response (hazard ratio 1.48, 95% CI 1.00–2.18).

In clinical practice settings, delivery of twice weekly sessions of CBT and IPT for depression is a way to improve depression treatment outcomes.

Care-as-usual (CAU) is often used as a control condition in psychotherapy research, but it may vary considerably what that entails, ranging from no treatment, to routine treatment in primary care, general medical care, perinatal care, and specialized mental health care.

We conducted a meta-analysis of trials comparing psychotherapy for depression to CAU, with a focus on the different categories of CAU and countries where the studies were conducted. We used an existing database of randomized trials on psychotherapy for depression that is updated every year.

A total of 140 studies with 15 419 patients were included. We found no significant differences in effects between categories of CAU (effect sizes ranging from g = 0.43 for CAU in primary care to g = 0.73 for no treatment), but heterogeneity was high in all CAU categories. After stratifying effects across specific countries (within CAU categories) we found that heterogeneity was considerably lower and there were several significant differences between countries. Overall, effects were larger in non-Western countries (g = 0.84 to 1.28) compared to those in Western countries (g = 0.52; p for difference = 0.002). Effects were smaller in studies with risk of bias (p = 0.01).

There are no significant differences between major categories of CAU when compared to psychotherapy conditions in randomized trials. However, effects of psychotherapy differ considerably across CAU conditions in specific countries. CAU therefore is a heterogeneous control condition in psychotherapy research.

Item 9 of the Patient Health Questionnaire-9 (PHQ-9) queries about thoughts of death and self-harm, but not suicidality. Although it is sometimes used to assess suicide risk, most positive responses are not associated with suicidality. The PHQ-8, which omits Item 9, is thus increasingly used in research. We assessed equivalency of total score correlations and the diagnostic accuracy to detect major depression of the PHQ-8 and PHQ-9.

We conducted an individual patient data meta-analysis. We fit bivariate random-effects models to assess diagnostic accuracy.

16 742 participants (2097 major depression cases) from 54 studies were included. The correlation between PHQ-8 and PHQ-9 scores was 0.996 (95% confidence interval 0.996 to 0.996). The standard cutoff score of 10 for the PHQ-9 maximized sensitivity + specificity for the PHQ-8 among studies that used a semi-structured diagnostic interview reference standard (N = 27). At cutoff 10, the PHQ-8 was less sensitive by 0.02 (−0.06 to 0.00) and more specific by 0.01 (0.00 to 0.01) among those studies (N = 27), with similar results for studies that used other types of interviews (N = 27). For all 54 primary studies combined, across all cutoffs, the PHQ-8 was less sensitive than the PHQ-9 by 0.00 to 0.05 (0.03 at cutoff 10), and specificity was within 0.01 for all cutoffs (0.00 to 0.01).

PHQ-8 and PHQ-9 total scores were similar. Sensitivity may be minimally reduced with the PHQ-8, but specificity is similar.

Studies of psychological interventions for the prevention of depression have found significant effects in the short-term, but the long-term efficacy has yet to be determined. This study evaluated the 8-year effect of a randomized controlled trial for indicated prevention of depression in female caregivers.

A total of 173 non-professional female caregivers with subclinical depressive symptoms not meeting criteria for a major depressive episode (MDE) were randomized to either a brief problem-solving intervention (n = 89) or usual-care control group (n = 84). Blinded evaluators conducted an assessment at the 8-year follow-up. The primary outcome was Depression Status, defined by diagnoses of MDE since the 1-year follow-up using the Structured Clinical Interview for the Disorders of the DSM-5. The secondary outcome was current Depressive Symptom Severity. Regression analyses were conducted to evaluate the effect of the intervention on the outcomes.

There were no significant differences in the Depression Status between the problem-solving (30.3%) and control groups (26.2%) (adjusted OR 1.25, 95% CI −0.58 to 2.69). Depressive Symptom Severity, however, was significantly lower in the problem-solving group compared to the control group at this follow-up, amounting to a small effect size of Cohen's d = 0.39 (adjusted B = −3.32, p = 0.018).

This is the first study to assess such a long-term follow-up of intervention of indicated prevention of depression. Results seem to indicate that the protective effect of the intervention became smaller over time during follow-up. Future research should replicate these results.

The Hamilton Depression Rating Scale (HAMD) and the Beck Depression Inventory (BDI) are the most frequently used observer-rated and self-report scales of depression, respectively. It is important to know what a given total score or a change score from baseline on one scale means in relation to the other scale.

We obtained individual participant data from the randomised controlled trials of psychological and pharmacological treatments for major depressive disorders. We then identified corresponding scores of the HAMD and the BDI (369 patients from seven trials) or the BDI-II (683 patients from another seven trials) using the equipercentile linking method.

The HAMD total scores of 10, 20 and 30 corresponded approximately with the BDI scores of 10, 27 and 42 or with the BDI-II scores of 13, 32 and 50. The HAMD change scores of −20 and −10 with the BDI of −29 and −15 and with the BDI-II of −35 and −16.

The results can help clinicians interpret the HAMD or BDI scores of their patients in a more versatile manner and also help clinicians and researchers evaluate such scores reported in the literature or the database, when scores on only one of these scales are provided. We present a conversion table for future research.

Different diagnostic interviews are used as reference standards for major depression classification in research. Semi-structured interviews involve clinical judgement, whereas fully structured interviews are completely scripted. The Mini International Neuropsychiatric Interview (MINI), a brief fully structured interview, is also sometimes used. It is not known whether interview method is associated with probability of major depression classification.

To evaluate the association between interview method and odds of major depression classification, controlling for depressive symptom scores and participant characteristics.

Data collected for an individual participant data meta-analysis of Patient Health Questionnaire-9 (PHQ-9) diagnostic accuracy were analysed and binomial generalised linear mixed models were fit.

A total of 17 158 participants (2287 with major depression) from 57 primary studies were analysed. Among fully structured interviews, odds of major depression were higher for the MINI compared with the Composite International Diagnostic Interview (CIDI) (odds ratio (OR) = 2.10; 95% CI = 1.15–3.87). Compared with semi-structured interviews, fully structured interviews (MINI excluded) were non-significantly more likely to classify participants with low-level depressive symptoms (PHQ-9 scores ≤6) as having major depression (OR = 3.13; 95% CI = 0.98–10.00), similarly likely for moderate-level symptoms (PHQ-9 scores 7–15) (OR = 0.96; 95% CI = 0.56–1.66) and significantly less likely for high-level symptoms (PHQ-9 scores ≥16) (OR = 0.50; 95% CI = 0.26–0.97).

The MINI may identify more people as depressed than the CIDI, and semi-structured and fully structured interviews may not be interchangeable methods, but these results should be replicated.

Drs Jetté and Patten declare that they received a grant, outside the submitted work, from the Hotchkiss Brain Institute, which was jointly funded by the Institute and Pfizer. Pfizer was the original sponsor of the development of the PHQ-9, which is now in the public domain. Dr Chan is a steering committee member or consultant of Astra Zeneca, Bayer, Lilly, MSD and Pfizer. She has received sponsorships and honorarium for giving lectures and providing consultancy and her affiliated institution has received research grants from these companies. Dr Hegerl declares that within the past 3 years, he was an advisory board member for Lundbeck, Servier and Otsuka Pharma; a consultant for Bayer Pharma; and a speaker for Medice Arzneimittel, Novartis, and Roche Pharma, all outside the submitted work. Dr Inagaki declares that he has received grants from Novartis Pharma, lecture fees from Pfizer, Mochida, Shionogi, Sumitomo Dainippon Pharma, Daiichi-Sankyo, Meiji Seika and Takeda, and royalties from Nippon Hyoron Sha, Nanzando, Seiwa Shoten, Igaku-shoin and Technomics, all outside of the submitted work. Dr Yamada reports personal fees from Meiji Seika Pharma Co., Ltd., MSD K.K., Asahi Kasei Pharma Corporation, Seishin Shobo, Seiwa Shoten Co., Ltd., Igaku-shoin Ltd., Chugai Igakusha and Sentan Igakusha, all outside the submitted work. All other authors declare no competing interests. No funder had any role in the design and conduct of the study; collection, management, analysis and interpretation of the data; preparation, review or approval of the manuscript; and decision to submit the manuscript for publication.

Little is known about potential harmful effects as a consequence of self-guided internet-based cognitive behaviour therapy (iCBT), such as symptom deterioration rates. Thus, safety concerns remain and hamper the implementation of self-guided iCBT into clinical practice. We aimed to conduct an individual participant data (IPD) meta-analysis to determine the prevalence of clinically significant deterioration (symptom worsening) in adults with depressive symptoms who received self-guided iCBT compared with control conditions. Several socio-demographic, clinical and study-level variables were tested as potential moderators of deterioration.

Randomised controlled trials that reported results of self-guided iCBT compared with control conditions in adults with symptoms of depression were selected. Mixed effects models with participants nested within studies were used to examine possible clinically significant deterioration rates.

Thirteen out of 16 eligible trials were included in the present IPD meta-analysis. Of the 3805 participants analysed, 7.2% showed clinically significant deterioration (5.8% and 9.1% of participants in the intervention and control groups, respectively). Participants in self-guided iCBT were less likely to deteriorate (OR 0.62, p < 0.001) compared with control conditions. None of the examined participant- and study-level moderators were significantly associated with deterioration rates.

Self-guided iCBT has a lower rate of negative outcomes on symptoms than control conditions and could be a first step treatment approach for adult depression as well as an alternative to watchful waiting in general practice.

Problem-solving therapy (PST) is one of the best examined types of psychotherapy for adult depression. No recent meta-analysis has examined the effects of PST compared to control groups or to other treatments. We wanted to verify whether PST is effective, whether effects are comparable to those of other treatments, and whether we could identify the possible sources of high heterogeneity that was found in earlier meta-analyses.

We conducted systematic searches in bibliographical databases, including PubMed, PsycInfo, Embase and the Cochrane database of randomized trials.

We included 30 randomized controlled trials on PST (with 3530 patients), in which PST was compared to control conditions, with other therapies, and with pharmacotherapy. We could compare these 30 trials on PST also with 259 trials on other psychotherapies for adult depression. The effect size of PST versus control groups was g = 0.79 (0.57–1.01) with very high heterogeneity (I2 = 84; 95% CI: 77–88). The effect size from the 9 studies with low risk of bias was g = 0.34 (95% CI: 0.22–0.46) with low heterogeneity (I2 = 32; 95% CI: 0–68), which is comparable to the effects of other psychotherapies. PST was a little more effective than other therapies in direct comparisons, but that may be explained by the considerable number of studies with researcher allegiance towards PST. In meta-regression analyses of all controlled studies, no significant difference between PST and other therapies was found.

PST is probably an effective treatment for depression, with effect sizes that are small, but comparable to those found for other psychological treatments of depression.

More than half of patients who present with depressive disorders also have elevated comorbid anxiety symptoms. Given the high comorbidity between these disorders, it is important to understand the extent that psychotherapies for depression additionally ameliorate symptoms of anxiety.

Systematic searches were conducted in PubMed, PSYCinfo, EMBASE, and the Cochrane Registry of Controlled Trials. Included studies were randomized controlled trials that compared psychotherapy compared with a control condition for the treatment of adults with a primary diagnosis or elevated symptoms of depression and that examined the effects of treatment on anxiety outcomes. Acute phase depression and anxiety (continuous measure) outcomes were extracted. Effect sizes were calculated by subtracting the average post-treatment scores of the psychotherapy group from the average post-treatment scores of the comparison group divided by the pooled standard deviation.

Fifty-two studies of varying quality met the inclusion criteria. Pooled effect sizes showed that anxiety outcomes were significantly lower in the psychotherapy conditions than in control conditions at post-treatment [g = 0.52; 95% confidence interval (CI) 0.44–0.60; NNT (numbers-needed-to-treat) = 3.50]. Moderate heterogeneity was observed (I2 = 55%, 95% CI 40–66). Bivariate metaregression analysis revealed a significant association between depression and anxiety effect sizes at post-treatment Longer-term follow-ups of up to 14 months post-baseline showed indications for a small lasting effect of psychotherapy on anxiety outcomes (g = 0.27).

This meta-analysis provides evidence that psychotherapy aimed at depression can also reduce anxiety symptoms in relation to control conditions.

It is not clear whether relaxation therapies are more or less effective than cognitive and behavioural therapies in the treatment of anxiety. The aims of the present study were to examine the effects of relaxation techniques compared to cognitive and behavioural therapies in reducing anxiety symptoms, and whether they have comparable efficacy across disorders.

We conducted a meta-analysis of 50 studies (2801 patients) comparing relaxation training with cognitive and behavioural treatments of anxiety.

The overall effect size (ES) across all anxiety outcomes, with only one combined ES in each study, was g = −0.27 [95% confidence interval (CI) = −0.41 to −0.13], favouring cognitive and behavioural therapies (number needed to treat = 6.61). However, no significant difference between relaxation and cognitive and behavioural therapies was found for generalized anxiety disorder, panic disorder, social anxiety disorder and specific phobias (considering social anxiety and specific phobias separately). Heterogeneity was moderate (I2 = 52; 95% CI = 33–65). The ES was significantly associated with age (p < 0.001), hours of cognitive and/or behavioural therapy (p = 0.015), quality of intervention (p = 0.007), relaxation treatment format (p < 0.001) and type of disorder (p = 0.008), explaining an 82% of variance.

Relaxation seems to be less effective than cognitive and behavioural therapies in the treatment of post-traumatic stress disorder, and obsessive–compulsive disorder and it might also be less effective at 1-year follow-up for panic, but there is no evidence that it is less effective for other anxiety disorders.

The influence of baseline severity has been examined for antidepressant medications but has not been studied properly for cognitive–behavioural therapy (CBT) in comparison with pill placebo.

To synthesise evidence regarding the influence of initial severity on efficacy of CBT from all randomised controlled trials (RCTs) in which CBT, in face-to-face individual or group format, was compared with pill-placebo control in adults with major depression.

A systematic review and an individual-participant data meta-analysis using mixed models that included trial effects as random effects. We used multiple imputation to handle missing data.

We identified five RCTs, and we were given access to individual-level data (n = 509) for all five. The analyses revealed that the difference in changes in Hamilton Rating Scale for Depression between CBT and pill placebo was not influenced by baseline severity (interaction P = 0.43). Removing the non-significant interaction term from the model, the difference between CBT and pill placebo was a standardised mean difference of –0.22 (95% CI –0.42 to –0.02, P = 0.03, I 2 = 0%).

Patients suffering from major depression can expect as much benefit from CBT across the wide range of baseline severity. This finding can help inform individualised treatment decisions by patients and their clinicians.

Sponsorship bias has never been investigated for non-pharmacological treatments like psychotherapy.

We examined industry funding and author financial conflict of interest (COI) in randomised controlled trials directly comparing psychotherapy and pharmacotherapy in depression.

We conducted a meta-analysis with subgroup comparisons for industry v. non-industry-funded trials, and respectively for trial reports with author financial COI v. those without.

In total, 45 studies were included. In most analyses, pharmacotherapy consistently showed significant effectiveness over psychotherapy, g = −0.11 (95% CI −0.21 to −0.02) in industry-funded trials. Differences between industry and non-industry-funded trials were significant, a result only partly confirmed in sensitivity analyses. We identified five instances where authors of the original article had not reported financial COI.

Industry-funded trials for depression appear to subtly favour pharmacotherapy over psychotherapy. Disclosure of all financial ties with the pharmaceutical industry should be encouraged.

Several meta-analyses have shown that psychotherapy is effective for reducing depressive symptom severity. However, the impact on quality of life (QoL) is as yet unknown.

To investigate the effectiveness of psychotherapy for depression on global QoL and on the mental health and physical health components of QoL.

We conducted a meta-analysis of 44 randomised clinical trials comparing psychotherapy for adults experiencing clinical depression or elevated depressive symptoms with a control group. We used subgroup analyses to explore the influence of various study characteristics on the effectiveness of treatment.

We detected a small to moderate effect size (Hedges' g = 0.33, 95% CI 0.24–0.42) for global QoL, a moderate effect size for the mental health component (g = 0.42, 95% CI 0.33–0.51) and, after removing an outlier, a small but statistically significant effect size for the physical health component (g = 0.16, 95% CI 0.05–0.27). Multivariate meta-regression analyses showed that the effect size of depressive symptoms was significantly related to the effect size of the mental health component of QoL. The effect size of depressive symptoms was not related to global QoL or the physical health component.

Psychotherapy for depression has a positive impact on the QoL of patients with depression. Improvements in QoL are not fully explained by improvements in depressive symptom severity.

Psychological interventions may be beneficial in bipolar disorder.

To evaluate the efficacy of psychological interventions for adults with bipolar disorder.

A systematic review of randomised controlled trials was conducted. Outcomes were meta-analysed using RevMan and confidence assessed using the GRADE method.

We included 55 trials with 6010 participants. Moderate-quality evidence associated individual psychological interventions with reduced relapses at post-treatment (risk ratio (RR) = 0.66, 95% CI 0.48–0.92) and follow-up (RR = 0.74, 95% CI 0.63–0.87), and collaborative care with a reduction in hospital admissions (RR =0.68, 95% CI 0.49–0.94). Low-quality evidence associated group interventions with fewer depression relapses at post-treatment and follow-up, and family psychoeducation with reduced symptoms of depression and mania.

There is evidence that psychological interventions are effective for people with bipolar disorder. Much of the evidence was of low or very low quality thereby limiting our conclusions. Further research should identify the most effective (and cost-effective) interventions for each phase of this disorder.