articleBrief psychological therapies for anxiety and depression in primary care : meta-analysis and meta-regression

Background: Psychological therapies provided in primary care are usually briefer than in secondary care. There has been no recent comprehensive review comparing their effectiveness for common mental health problems. We aimed to compare the effectiveness of different types of brief psychological therapy administered within primary care across and between anxiety, depressive and mixed disorders. Methods: Meta-analysis and meta-regression of randomized controlled trials of brief psychological therapies of adult patients with anxiety, depression or mixed common mental health problems treated in primary care compared to primary care treatment as usual. Results: Thirty-four studies, involving 3962 patients, were included. Most were of brief cognitive behaviour therapy (CBT; n = 13), counselling (n = 8) or problem solving therapy (PST; n = 12). There was differential effectiveness between studies of CBT, with studies of CBT for anxiety disorders having a pooled effect size [d -1.06, 95% confidence interval (CI) -1.31 to -0.80] greater than that of studies of CBT for depression (d -0.33, 95% CI -0.60 to -0.06) or studies of CBT for mixed anxiety and depression (d -0.26, 95% CI -0.44 to -0.08). Counselling for depression and mixed anxiety and depression (d -0.32, 95% CI -0.52 to -0.11) and problem solving therapy (PST) for depression and mixed anxiety and depression (d -0.21, 95% CI -0.37 to -0.05) were also effective. Controlling for diagnosis, meta-regression found no difference between CBT, counselling and PST. Conclusions: Brief CBT, counselling and PST are all effective treatments in primary care, but effect sizes are low compared to longer length treatments. The exception is brief CBT for anxiety, which has comparable effect sizes. Background Anxiety and depressive disorders are common, with estimated combined prevalence varying between countries but over 10% in most Western countries [1-4]. The majority of such patients are treated in primary care, with few patients referred on to secondary mental health services [5,6]. With access to psychological therapies being limited [7], psychological therapy provided within primary care settings for depression and anxiety is usually brief [8]. In the UK, six sessions is a common treatment length [9]. This contrasts to the treatment lengths of 12 24 sessions which have been the subject of most efficacy trials of psychological therapies in secondary care settings [10,11]. Most reviews of psychological therapies combine primary and secondary care studies [11-13]. Recent reviews which have included analyses limited to primary care, have focussed on studies of patients with a diagnosis of depression [14-18] or studies of a specific type of psychological therapy [19]. Although studies of psychological therapies in primary care frequently include patients with both anxiety and depression, reflecting the heterogeneous patient presentations in primary care where mixed anxiety and depression is the most common diagnosis [20-22], such studies are excluded when the selection criteria for reviews are limited to single mental health diagnoses. The only reviews covering the range of mental * Correspondence: j.cape@ucl.ac. uk 1 Camden and Islington NHS Foundation Trust, St Pancras Hospital, 4 St Pancras Way, London NW1 0PE, UK Full list of author information is available at the end of the article © 2010 Cape et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cape et al. BMC Medicine 2010, 8:38 http://www.biomedcentral. com/1741-7015/8/38 Page 2 of 13 health disorders and types of psychological therapies used within primary care date back over a decade [23-26]. This systematic review, meta-analysis and meta-regression includes studies of anxiety, depression and mixed common mental health problems. It compares the effectiveness of different types of brief psychological therapies within primary care across and between disorders compared to treatment as usual. In the absence of studies directly comparing different types of psychological therapy provided in primary care (with one exception [27]), such comparisons are needed to help inform decisions about treatment. Methods Search strategy Studies were identified as part of a broader search of intervention studies in primary care mental health. The Medline, Embase and Psycinfo databases from inception to July 2008 were searched using a sensitive search strategy involving combinations of 'mental health' ('mental health' or psychol* or anx* or depress* or schizo* or dysthymi* or psychiatr* or emotion* or counsel*) and 'primary care' terms ('primary care' or 'primary health care' or 'family physician*' or 'practice nurs*' or 'general pract*' or GP*) in order to maximize identification of relevant interventions. Additional papers were identified from reference lists, from hand searching key journals and from contact with other primary care mental health researchers. All searches were limited to peer-reviewed published works in English. Inclusion criteria For this review, we included published randomized controlled trials of brief psychological therapies for adult patients with anxiety, depression, unspecified common mental health problems or 'emotional distress' provided by someone other than the patient's general practitioner (GP) either in primary care or at home organized from primary care. 'Brief ' was operationalized as more than two and less than 10 appointments, this number being a pragmatic choice on the grounds that it clusters around the six sessions commonly offered in primary care in the UK and is clearly fewer than the 12 24 sessions usually provided in secondary care efficacy trials. Studies of computerized or facilitated self-help [28-30], of psycho-educational groups [31,32], and of psychological therapy carried out as part of or referral on from case management within collaborative care [33], were excluded. Data extraction Data from included studies were extracted into structured summary tables. Studies were classified according to type of psychological therapy and whether patients included had major depressive disorder (MDD), minor depression, mixed depression, anxiety or 'mixed anxiety and depression' (where participants with a range of diagnoses of anxiety, depression, unspecified common mental health problems or 'emotional distress' were included). Outcome data closest to 4 months from baseline were extracted where there was more than one follow-up period, as this was the most common follow-up interval used in our initial set of studies. Other information extracted included: details of the participants; study country; length of follow-up (weeks from baseline); number of treatment sessions; study design (individually randomized or cluster randomized); method of randomization and allocation concealment; use of intention-to-treat analysis; primary symptom outcome measure(s); data of publication; number of participants randomized and attrition from each group. The data were initially extracted by one reviewer, with the results being checked by a second reviewer who extracted the outcome data independently, but otherwise was not blinded to the findings of the first reviewer. Disagreements between reviewers were resolved by discussion. The quality of each study was assessed by one reviewer who examined the adequacy of randomization and allocation concealment, and attrition using a modified version of the SIGN quality checklist for randomized controlled trials [34]. A second reviewer, blinded to the findings of the first reviewer, checked a sample of papers for reliability of the quality assessment. Meta-analysis Comprehensive meta analysis (CMA) software, Version 2.2.040 [35] was used to calculate the standardized mean difference (d) and associated standard error for each study, computed from means and standard deviations (adjusted for baseline differences if reported) or from the sample size and P-value from an appropriate betweengroups tor F-test if no other data were reported. We used data from an intention-to-treat analysis, with last observation carried forward, rather than data from participants who completed the study, if both were reported. Where a study only reported data from dichotomous outcomes (remission or response to treatment), we assumed that participants who ceased to engage in the study from whatever group had an unfavourable outcome, then converted the log odds ratio into d using CMA. For the purposes of the review, negative values of d indicate that the outcome favoured the intervention. The metan command in Stata Version 9.2 [36] was used to produce forest plots and summary effects using a random-effects model. We used I2 and the Q test of heterogeneity [37,38] to examine among-study variation in the meta-analysis. Significant variation was confirmed by visual inspection of the forest plots. I2 describes the proportion of total variaCape et al. BMC Medicine 2010, 8:38 http://www.biomedcentral. com/1741-7015/8/38 Page 3 of 13 tion in study effect sizes that is due to heterogeneity as opposed to sampling error, with 25%, 50% and 75% indicating low, moderate and high heterogeneity [38]. We conducted planned sub-group analyses based on both type of psychological therapy and diagnosis. Sensitivity analyses were used to examine how robust these findings were to assumptions made when calculating effect size. To check for publication bias, CMA was used to generate funnel plots and Egger's regression asymmetry test [39]. Where asymmetry was detected, we assessed the potential impact of the publication bias using the Duval and Tweedie nonparametric 'trim and fill' method [40]. This method recalculates the effect size given the presence of publication bias. Meta-regressi