The efficacy of psychotherapy and pharmacotherapy in treating depressive and anxiety disorders: a meta-analysis of direct comparisons

Authors

  • Pim Cuijpers,

    1. Department of Clinical Psychology, VU University Amsterdam, BT Amsterdam, The Netherlands
    2. EMGO Institute for Health and Care Research, VU University and VU University Medical Center, Amsterdam, The Netherlands
    3. Leuphana University, Lünebrug, Germany
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  • Marit Sijbrandij,

    1. Department of Clinical Psychology, VU University Amsterdam, BT Amsterdam, The Netherlands
    2. EMGO Institute for Health and Care Research, VU University and VU University Medical Center, Amsterdam, The Netherlands
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  • Sander L. Koole,

    1. Department of Clinical Psychology, VU University Amsterdam, BT Amsterdam, The Netherlands
    2. EMGO Institute for Health and Care Research, VU University and VU University Medical Center, Amsterdam, The Netherlands
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  • Gerhard Andersson,

    1. Department of Behavioural Sciences and Learning, Swedish Institute for Disability Research, University of Linköping, Sweden
    2. Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Stockholm, Sweden
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  • Aartjan T. Beekman,

    1. EMGO Institute for Health and Care Research, VU University and VU University Medical Center, Amsterdam, The Netherlands
    2. Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands
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  • Charles F. Reynolds III

    1. Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Abstract

Although psychotherapy and antidepressant medication are efficacious in the treatment of depressive and anxiety disorders, it is not known whether they are equally efficacious for all types of disorders, and whether all types of psychotherapy and antidepressants are equally efficacious for each disorder. We conducted a meta-analysis of studies in which psychotherapy and antidepressant medication were directly compared in the treatment of depressive and anxiety disorders. Systematic searches in bibliographical databases resulted in 67 randomized trials, including 5,993 patients that met inclusion criteria, 40 studies focusing on depressive disorders and 27 focusing on anxiety disorders. The overall effect size indicating the difference between psychotherapy and pharmacotherapy after treatment in all disorders was g=0.02 (95% CI: −0.07 to 0.10), which was not statistically significant. Pharmacotherapy was significantly more efficacious than psychotherapy in dysthymia (g=0.30), and psychotherapy was significantly more efficacious than pharmacotherapy in obsessive-compulsive disorder (g=0.64). Furthermore, pharmacotherapy was significantly more efficacious than non-directive counseling (g=0.33), and psychotherapy was significantly more efficacious than pharmacotherapy with tricyclic antidepressants (g=0.21). These results remained significant when we controlled for other characteristics of the studies in multivariate meta-regression analysis, except for the differential effects in dysthymia, which were no longer statistically significant.

Depressive and anxiety disorders are highly prevalent [1, 2] and associated with high levels of service use, a considerable disease burden [3], substantial economic costs [4-6], and a significant loss of quality of life for patients and their relatives [7, 8]. Several efficacious treatments for depressive and anxiety disorders are available, including different forms of psychotherapy and antidepressant medication [9-11]. Although both types of treatment have been found to be efficacious, it is not known whether they are equally efficacious for all types of depressive and anxiety disorders. There is evidence from meta-analyses of studies comparing psychotherapy and pharmacotherapy directly that they are about equally efficacious in depression [12] and generalized anxiety disorder (GAD) [13]. It is not clear whether this is true for all depressive and anxiety disorders. For example, for obsessive-compulsive disorder (OCD) and social anxiety disorder (SAD), no meta-analyses of direct comparisons between psychotherapy and pharmacotherapy have been conducted yet, even though a considerable number of such comparative trials have been carried out.

Furthermore, it remains unclear whether all types of psychotherapy and all types of antidepressant medications have comparable effects. In one previous meta-analysis, we found that treatment with selective serotonin reuptake inhibitors (SSRIs) was somewhat more effective than treatment with psychotherapy [12], whereas tricyclic antidepressants (TCAs) and psychotherapy were equally effective. A re-analysis of those data, however, showed that there were no significant differences between psychotherapy and SSRIs after adjusting for differential drop-out from both treatments. Another meta-analysis confirmed that psychotherapy and SSRIs were equally effective, when only bona fide psychotherapies were included [14].

It is also possible that there are differences between different forms of psychotherapy. There are some indications from meta-analytic research that interpersonal psychotherapy (IPT) may be somewhat more efficacious than other psychotherapies in the treatment of depression [15, 16], although this is not confirmed in all meta-analyses [17]. There are also some indications that psychodynamic psychotherapy [18] and non-directive supportive counselling [19] may be somewhat less efficacious than other psychotherapies. Given these potential differences between psychotherapies, it is conceivable that the differential effects of psychotherapy and pharmacotherapy may depend on the type of psychotherapy. Earlier meta-analyses may have failed to detect these differential effects because of the small number of included studies and the resulting lack of statistical power.

We report here the results of an overall meta-analysis of the studies in which psychotherapy and antidepressant medication for depressive and anxiety disorders were directly compared with each other.

METHODS

Identification and selection of studies

Several strategies were used to identify relevant studies. We searched four major bibliographical databases (PubMed, PsycInfo, EMBASE and the Cochrane database of randomized trials) by combining terms indicative of each of the disorders with terms indicative of psychological treatment (both MeSH terms and text words) and randomized controlled trials. We also checked the references of 116 earlier meta-analyses of psychological treatments for the included disorders. Details of the searches and exact search strings are given in Figure 1.

Figure 1.

Selection and inclusion of studies

We included randomized trials in which the effects of a psychological treatment were directly compared with the effects of antidepressant medication in adults with depressive disorder, panic disorder with or without agoraphobia, GAD, SAD, OCD, or post-traumatic stress disorder (PTSD). Only studies in which subjects met diagnostic criteria for the disorder according to a structured diagnostic interview – such as the Structured Clinical Interview for DSM-IV (SCID), the Composite International Diagnostic Interview (CIDI) or the Mini International Neuropsychiatric Interview (MINI) – were included. Comorbid mental or somatic disorders were not used as an exclusion criterion. Studies on inpatients, adolescents and children (below 18 years of age) were excluded. We also excluded maintenance studies, aimed at people who had already recovered or partly recovered after an earlier treatment, and studies on other types of medication, such as benzodiazepines for anxiety disorders. Studies in English, German, Spanish and Dutch were considered for inclusion.

Quality assessment and data extraction

We evaluated the quality of included studies using the Cochrane Collaboration “risk of bias” assessment tool [20]. This tool assesses possible sources of bias in randomized trials, including the adequate generation of allocation sequence, the concealment of allocation to conditions, the prevention of knowledge of the allocated intervention (masking of assessors), and dealing with incomplete outcome data (this was rated as positive when intention-to-treat analyses were conducted, meaning that all randomized patients were included in the analyses). The assessment was conducted by two independent researchers, and disagreements were solved through discussion.

We also coded the participant characteristics (disorder, recruitment method, target group); the type of antidepressant which was used (SSRI, TCA, monoamine oxidase inhibitor (MAOI), other or protocolized treatment including several antidepressants); and the characteristics of the psychotherapy (format, number of sessions, and type of psychotherapy). The types of psychotherapy we identified were cognitive-behavioral therapy (CBT), IPT, problem-solving therapy, non-directive supportive counselling, psychodynamic psychotherapy, and others. Although CBTs used a mix of different techniques, we clustered them together in one group. We rated a therapy as CBT when it included cognitive restructuring or a behavioral approach (such as exposure and response prevention). When a therapy used a mix of CBT and IPT, we rated it as “other”, along with other therapeutic approaches.

Meta-analyses

For each comparison between a psychotherapy and a pharmacotherapy, the effect size indicating the difference between the two groups at post-test (Hedges' g) was evaluated. Effect sizes were calculated by subtracting (at post-test) the average score of the psychotherapy group from the average score of the pharmacotherapy group, and dividing the result by the pooled standard deviation. Because some studies had relatively small sample sizes, we corrected the effect size for small sample bias [21].

In the calculations of effect sizes in studies of patients with depressive disorders, we used only those instruments that explicitly measured symptoms of depression. In studies examining anxiety disorders, we only used instruments that explicitly measured symptoms of anxiety. If more than one measure was used, the mean of the effect sizes was calculated, so that each study provided only one effect size. If means and standard deviations were not reported, we used the procedures of the Comprehensive Meta-Analysis software (version 2.2.021) to calculate the effect size using dichotomous outcomes; and if these were not available either, we used other statistics (such a t value or p value). To calculate pooled mean effect sizes, we also used the Comprehensive Meta-Analysis software. Because we expected considerable heterogeneity among the studies, we employed a random effects pooling model in all analyses.

We only examined the differential effects at post-test and did not look at the longer-term effects. The types of outcomes reported at follow-up and the follow-up periods differed widely between studies. Furthermore, some studies reported only naturalistic outcomes, while others delivered booster sessions and maintenance treatments during the whole follow-up period or part of it. Because of these large differences, we decided it was not meaningful to pool the results of these outcomes.

As a test of homogeneity of effect sizes, we calculated the I2 statistic. A value of 0% indicates no observed heterogeneity, and higher values indicate increasing heterogeneity, with 25% as low, 50% as moderate, and 75% as high heterogeneity [22]. We calculated 95% confidence intervals around I2 [23] using the non-central chi-squared-based approach within the Heterogi module for Stata [24].

We conducted subgroup analyses according to the mixed effects model, in which studies within subgroups are pooled with the random effects model, while tests for significant differences between subgroups are conducted with the fixed effects model. For continuous variables, we used meta-regression analyses to test whether there was a significant relationship between the continuous variable and the effect size, as indicated by a Z value and an associated p value.

We tested for publication bias by inspecting the funnel plot on primary outcome measures and by Duval and Tweedie's trim and fill procedure [25], which yields an estimate of the effect size after the publication bias has been taken into account. We also conducted Egger's test of the intercept to quantify the bias captured by the funnel plot and test whether it was significant.

Multivariate meta-regression analyses were conducted with the effect size as the dependent variable. To decide which variables should be entered as predictors in the regression model, we first defined a reference group within each category of variables. To avoid collinearity among the predictors of the regression model, we first examined whether high correlations were found among the variables that could be entered into the model. Next, we calculated the correlations between all predictors (except the reference variables). Because no correlations were higher than r=0.60, all predictors could be entered in the regression models. Multivariate regression analyses were conducted in STATA MP, version 11 for Mac.

RESULTS

Selection and inclusion of studies

After examining a total of 21,729 abstracts (14,903 after removal of duplicates), we retrieved 2,278 full-text papers for further consideration. We excluded 2,211 of the retrieved papers. The flow chart describing the inclusion process, including the reasons for exclusion, is presented in Figure 1. A total of 67 studies met the inclusion criteria for this meta-analysis. Selected characteristics of the included studies [26-92] are reported in Table 1.

Table 1. Selected characteristics of included studies
StudyDisorderPsychotherapyMedicationQualityaCountry
  1. a

    A positive or negative sign is given for four quality criteria: allocation sequence, concealment of allocation to conditions, blinding of assessors, and intention-to-treat analysis

  2. GAD – generalized anxiety disorder, PAN – panic disorder with or without agoraphobia, MDD – major depressive disorder, Mood – mixed mood disorder, SAD – social anxiety disorder, DYS – dysthymic disorder, OCD – obsessive-compulsive disorder, PTSD – post-traumatic stress disorder, CBT – cognitive-behavioral therapy, DYN – psychodynamic therapy, PST – problem-solving therapy, BT – behavior therapy, IPT – interpersonal psychotherapy, REBT – rational emotive behavior therapy, CBASP – cognitive behavioral analysis system of psychotherapy, EMDR – eye movement desensitization and reprocessing, Supp Ex – supportive-expressive therapy, ind – individual format, grp – group format, gp – delivered by a general practitioner, n – delivered by a nurse, TCA – tricyclic antidepressant, SSRI – selective serotonin reuptake inhibitor, MAOI – monoamine oxidase inhibitor, SNRI – serotonin-norepinephrine reuptake inhibitor

Bakhshani et al [26]GADCBT (n=7)TCA (n=7)− − − +Iran
Bakker et al [27]PANCBT (n=35)SSRI (n=32)− − − +Europe
   TCA (n=32)  
Barber et al [28]MDDDYN (n=51)Mixed/other (n=55)− − + +USA
Barlow et al [29]PANCBT (n=65)TCA (n=83)− − + +USA
Barrett et al [30]MoodPST (n=80)SSRI (n=80)+ + + +USA
Bedi et al [31]MDDCounseling (n=39)Mixed/other (n=44)+ + − −Europe
Black et al [32]PANCBT (n=25)SSRI (n=25)− − − −USA
Blackburn & Moore [33]MDDCBTMixed/other− − − +Europe
Blanco et al [34]SADCBT (n=32)MAOI (n=35)+ + + +USA
Blomhoff et al [35]SADBT (n=98)SSRI (n=95)+ + + +Europe
Browne et al [36]DYSIPT (n=122)SSRI (n=117)+ + + −Canada
Clark et al [37]PANCBT (n=16)TCA (n=16)− − + −Europe
Dannon et al [38]PANCBT (n=23)SSRI (n=27)− − − −Israel
David et al [39]MDDCBT (n=56)SSRI (n=57)− − + +Europe
  REBT (n=57)   
Davidson et al [40]SADCBT (n=42)SSRI (n=39)+ + + +USA
Dekker et al [41]MDDDYN (n=59)Mixed/other (n=44)− − + −Europe
Dunlop et al [42]MDDCBT (n=41)SSRI (n=39)+ + + +USA
Dunner et al [43]DYSCBT (n=9)SSRI (n=11)− − + −USA
Elkin et al [44]MDDIPT (n=61)TCA (n=57)+ + + +USA
  CBT (n=59)   
Faramarzi et al [45]MDDCBT (n=29)SSRI (n=30)− − + −Iran
Finkenzeller et al [46]MDDIPT (n=23)SSRI (n=24)+ − + +Europe
Foa et al [47]OCDBT (n=19)TCA (n=27)− − + −USA
Frank et al [48]MDDIPT (n=160)SSRI (n=158)− − + +USA
Frommberger et al [49]PTSDCBT (n=10)SSRI (n=11)− − − −Europe
Hegerl et al [50]MoodCBT (n=52)SSRI (n=76)+ + + +Europe
Heimberg et al [51]SADCBT (n=28)MAOI (n=27)− − + +USA
  Counseling (n=26)   
Hendriks et al [52]PANCBT (n=20)SSRI (n=17)+ + + +Europe
Hoexter et al [53]OCDCBT (n=13)SSRI (n=13)+ − + −Brazil
Hollon et al [54]MDDCBT (n=25)TCA (n=57)− − + +USA
Jarrett et al [55]MDDCBT (n=36)MAOI (n=36)+ + + +USA
Keller et al [56]MDDCBASP (n=226)SNRI (n=220)+ + + +USA
Kolk et al [57]PTSDEMDR (n=24)SSRI (n=26)− − + +USA
Koszycki et al [58]PANCBT (n=59)SSRI (n=62)+ + + +Canada
Lesperance et al [59]MDDIPT (n=67)SSRI (n=75)+ + + +Canada
Loerch et al [60]PANCBT (n=14)MAOI (n=16)− − + +Europe
Markowitz et al [61]DYSIPT (n=23)SSRI (n=24)− − + +USA
  Counseling (n=26)   
Marshall et al [62]MDDCBT (n=37)Mixed/other (n=30)− − − −Canada
  IPT (n=35)   
Martin et al [63]MDDIPT (n=13)SNRI (n=15)− − − +Europe
McBride et al [64]MDDCBT (n=21)Mixed/other (n=21)− − − −Canada
McKnight et al [65]MDDCBTTCA− − − −USA
McLean & Hakstian [66]MDDDYN (n=44)TCA (n=49)− − + −Canada
  BT (n=42)   
Miranda et al [67]MDDCBT (n=90)Mixed/other (n=88)+ + + +USA
Mohr et al [68]MDDCBT (n=20)SSRI (n=15)− − − +USA
  Supp Ex (n=19)   
Mörtberg et al [69]SADCBT ind (n=32)Mixed/other (n=33)+ + + +Europe
  CBT grp (n=35)   
Murphy et al [70]MDDCBT (n=22)TCA (n=24)+ + − +USA
Murphy et al [71]MDDPST (n=29)TCA (n=27)+ + + +Europe
Mynors-Wallis et al [72]MDDPST gp (n=39)SSRI (n=36)+ + + +Europe
  PST n (n=41)   
Nakatani et al [73]OCDBT (n=10)SSRI (n=10)− − + −Japan
Nazari et al [74]OCDEMDR (n=30)SSRI (n=30)− − + −Iran
Oosterbaan et al [75]SPHCBT (n=28)MAOI (n=27)− − + +Europe
Prasko et al [76]SPHCBT (n=22)MAOI (n=20)− − + −Europe
Ravindran et al [77]DYSCBT (n=24)SSRI (n=22)+ + + −Canada
Reynolds et al [78]MDDIPT (n=16)TCA (n=25)− − + +USA
Rush et al [79]MDDCBT (n=19)TCA (n=22)− − + +USA
Salminen et al [80]MDDDYN (n=26)SSRI (n=25)− − − +Europe
Schulberg et al [81]MDDIPT (n=93)TCA (n=91)− −+ +USA
Scott & Freeman [82]MDDCBT (n=29)TCA (n=26)+ + + +Europe
  Counseling (n=29)   
Shamsaei et al [83]MDDCBT (n=40)SSRI (n=40)+ − + −Iran
Shareh et al [84]OCDCBT (n=6)SSRI (n=6)− − − −Iran
Sharp et al [85]PANCBT (n=29)SSRI (n=29)− − − −Europe
Sharp et al [86]MoodCounseling (n=112)Mixed/other (n=106)+ + + +Europe
Sousa et al [87]OCDCBT (n=25)SSRI (n=25)− − + −Brazil
Spinhoven et al [88]PANCBT (n=20)SSRI (n=19)− − − +Europe
Thompson et al [89]MDDCBT (n=36)TCA (n=33)− − − +USA
Van Apeldoorn et al [90]PANCBT (n=36)Mixed/other (n=37)+ + + +Europe
Weissman et al [91]MDDIPT (n=23)TCA (n=20)− − + −USA
Williams et al [92]MoodPST (n=113)SSRI (n=106)+ + + +USA

Characteristics of included studies

In the 67 studies, a total of 5,993 patients participated (3,142 in the psychotherapy and 2,851 in the pharmacotherapy conditions). Forty studies focused on depressive disorders (32 on major depressive disorder, four on dysthymia, and four on mixed mood disorders) and 27 on anxiety disorders (11 on panic disorder with or without agoraphobia, six on OCD, seven on SAD, two on PTSD, and one on GAD). Many studies (n=32) recruited patients exclusively from clinical samples, and most (n=56) were aimed at adults in general instead of a more specific population (such as older adults or patients with a comorbid somatic disorder). Most psychotherapies (49 of the 78 that were examined in these studies) were characterized as CBT; 11 studies examined IPT, five problem-solving therapy, six non-directive counseling, four psychodynamic therapies, and the remaining three other therapies. Most therapies (n=62) used an individual treatment format, and the number of treatment sessions ranged from 6 to 20, with most therapies (n=45) having between 12 and 18 sessions. The antidepressants that were examined in the studies included SSRIs (n=37), TCAs (n=20), SNRIs (n=2), MAOIs (n=7), and treatment protocols with different types of antidepressant medication (n=12). Most studies were conducted in the United States (n=27) or in Europe (n=23).

Quality assessment

The quality of the studies varied. Twenty-seven studies reported an adequate sequence generation, while the other 40 did not. Twenty-four studies reported allocation to conditions by an independent (third) party. Forty-nine studies reported blinding of outcome assessors or used only self-report outcomes, whereas 18 did not report blinding. Forty-two studies conducted intention-to-treat analyses (a post-treatment score was analyzed for every patient even if the last observation prior to attrition had to be carried forward or that score was estimated from earlier response trajectories). Twenty studies met all four quality criteria, four studies met three criteria, and the remaining 43 studies met two criteria or less.

Comparative effects of psychotherapy and pharmacotherapy

The overall mean effect size indicating the difference between psychotherapy and pharmacotherapy at post-test for all 78 comparisons was 0.02 (95% CI: −0.07 to 0.10; Table 2), in favor of psychotherapy, but not significantly different from zero. Heterogeneity was moderate to high (I2=62; 95% CI: 52 to 70). The results of these overall analyses are presented in Figure 2.

Table 2. Comparative effects of psychotherapy and pharmacotherapy: subgroup analyses
  Ng95% CII295% CIp
  1. All subgroup analyses were conducted with the random effects model; a positive effect size indicates superior effects of psychotherapy; the p values indicate whether the effect sizes in the subgroups differ significantly from each other; significant values are highlighted in bold

  2. SAD – social anxiety disorder, OCD – obsessive-compulsive disorder, SSRI – selective serotonin reuptake inhibitor, TCA – tricyclic antidepressant, MAOI – monoamine oxidase inhibitor

All studies 780.02−0.07 to 0.106252 to 70 
Possible outliers removed68−0.07−0.14 to 0.014121 to 56 
One effect size per study (highest)670.06−0.03 to 0.156251 to 71 
One effect size per study (lowest)670.03−0.07 to 0.126251 to 71 
        
Mood disorders       
 Any mood disorder48−0.03−0.14 to 0.08520 to 470.01
 Major depression390.02−0.10 to 0.134622 to 63 
 Dysthymia5−0.30−0.60 to −0.00550 to 83 
 Mixed mood disorders4−0.14−0.45 to 0.17640 to 88 
Anxiety disorders       
 Any anxiety disorder300.10−0.05 to 0.257159 to 80 
 Panic disorder120.00−0.28 to 0.286228 to 79 
 SAD9−0.03−0.34 to 0.287450 to 87 
 OCD60.640.20 to 1.087236 to 88 
 Other30.24−0.39 to 0.8600 to 90 
Psychotherapy type       
 Cognitive-behavioral therapy490.09−0.03 to 0.206046 to 710.12
 Interpersonal psychotherapy11−0.09−0.31to 0.146533 to 82 
 Problem-solving therapy5−0.04−0.36 to 0.2700 to 79 
 Counseling6−0.33−0.64 to −0.026927 to 87 
 Other70.07−0.21 to 0.346727 to 85 
Treatment format       
 Individual620.02−0.08 to 0.126148 to 700.89
 Group140.03−0.18 to 0.257150 to 83 
Pharmacotherapy       
 SSRI370.01−0.12 to 0.135840 to 710.02
 TCA200.210.04 to 0.395219 to 71 
 MAOI7−0.05−0.34 to 0.258365 to 91 
 Mixed/protocol/other14−0.19−0.37 to 0.00495 to 72 
Recruitment       
 Only clinical samples360.07−0.06 to 0.205534 to 690.52
 Also community recruitment35−0.03−0.16 to 0.106550 to 76 
 Other recruitment method7−0.04−0.34 to 0.257649 to 89 
Country       
 USA31−0.07−0.21 to 0.075228 to 680.17
 Europe290.03−0.11 to 0.175634 to 71 
 Other180.15−0.04 to 0.347662 to 85 
Quality       
 Score 0–1310.10−0.06 to 0.256956 to 790.44
 Score 2–323−0.03−0.19 to 0.136546 to 78 
 Score 424−0.02−0.17 to 0.12380 to 62 
Figure 2.

Differential effects of psychotherapy and pharmacotherapy (Hedges' g)

Removing possible outliers (in which the 95% CI of the effect size did not overlap with the 95% CI of the pooled effect size) resulted in a small, non-significant effect size in favor of pharmacotherapy and somewhat lower heterogeneity (I2=41; low to moderate).

In this meta-analysis, we included ten studies in which two psychological treatments were compared with the same pharmacotherapy group, as well as one study in which one psychological treatment was compared with two different types of antidepressant medication. This means that multiple comparisons from these studies, not independent from each other, were included in the same analysis, which may have resulted in an artificial reduction of heterogeneity and may have affected the pooled effect size. We examined the possible effects of this by conducting an analysis in which we included only one effect size per study. First, we included only the comparison with the largest effect size from these studies and then we conducted another analysis in which we included only the smallest effect size. As can be seen from Table 2, the resulting effect sizes as well as the levels of heterogeneity were comparable with the overall analyses.

We found no indications for publication bias. The effect size did not change after adjusting for publication bias according to Duval and Tweedie's trim and fill procedure, and according to this procedure no missing study had to be imputed.

Univariate moderator analyses

We examined whether there were significant differences between psychotherapy and pharmacotherapy in specific subgroups of studies. The results of these subgroup analyses are presented in Table 2. We found that the effect size was significantly associated with the type of disorder (p<0.01). More specifically, we found that pharmacotherapy was more efficacious than psychotherapy in dysthymia (differential effect size: g=−0.30; 95% CI: −0.60 to −0.00; I2=55; 95% CI: 0 to 83). By contrast, psychotherapy was more efficacious than pharmacotherapy in OCD (differential effect size: g=0.64; 95% CI: 0.20 to 1.08; I2=72; 95% CI: 36 to 88).

We also found that type of pharmacotherapy was significantly associated with the differential effect size (p<0.05). Treatment with a TCA was significantly less efficacious than psychotherapy (g=0.21; 95% CI: 0.04 to 0.39; I2=52; 95% CI: 19 to 71), while there was no significant difference between other types of pharmacotherapy and psychotherapy. Furthermore, we found that treatment with non-directive supportive counseling was less efficacious than pharmacotherapy (g=−0.33; 95% CI: −0.64 to −0.02; I2=69; 95% CI: 27 to 87).

We did not find that the effect size was associated with the treatment format in psychotherapy, recruitment method of patients, country where the study was conducted, or the quality of the study.

Multivariate meta-regression analyses

Because we found several important moderators of outcome in the univariate moderator analyses, we decided to conduct a multivariate meta-regression analysis in which we entered the relevant predictors simultaneously. The results of these analyses are presented in Table 3. The effects of psychotherapy were still significantly higher than those of pharmacotherapy in studies on OCD, even after adjusting for other characteristics of the included studies. We also found that non-directive supportive counseling was still significantly less efficacious than pharmacotherapy, and TCAs remained significantly less efficacious than psychotherapy. In dysthymia, psychotherapy and pharmacotherapy did no longer differ significantly from each other.

Table 3. Standardized regression coefficients of characteristics of psychotherapy and pharmacotherapy studies
  Full modelParsimonious model
  Coef.95% CIpCoef.95% CIp
  1. MDD – major depressive disorder, SAD – social anxiety disorder, OCD – obsessive-compulsive disorder, CBT – cognitive-behavioral therapy, ITP – interpersonal psychotherapy, SSRI – selective serotonin reuptake inhibitor, TCA – tricyclic antidepressant, MAOI – monoamine oxidase inhibitor

Disorder       
 MDDRef.     
 Dysthymia−0.01−0.46 to 0.43    
 Other mood disorder0.02−0.42 to 0.45    
 Panic disorder−0.100.42 to 0.21    
 SAD0.12−0.28 to 0.53    
 OCD0.520.01 to 1.03<0.050.760.36 to 1.15<0.001
 Other anxiety disorder0.32−0.30 to 0.95    
Recruitment from clinical samples only0.05−0.17 to 0.26    
Adults in general vs. specific target group−0.41−0.70 to-0.13<0.01−0.27−0.50 to - 0.05<0.05
Psychotherapy       
 CBTRef.     
 ITP−0.16−0.45 to 0.12    
 Counseling−0.51−0.92 to −0.19<0.05−0.41−0.72 to −0.09<0.05
 Other therapy−0.03−0.39 to 0.33    
Pharmacotherapy       
 SSRIRef.     
 TCA0.320.06 to 0.58<0.050.310.11 to 0.50<0.01
 MAOI0.07−0.34 to 0.48    
 Other−0.23−0.51 to 0.05    
Individual psychotherapy format0.01−0.27 to 0.28    
Number of psychotherapy sessions0.01−0.02 to 0.04    
Quality of study0.00−0.07 to 0.08    
Country       
 USARef.     
 Europe0.260.03 to 0.49<0.050.180.00 to 0.36<0.05
 Other−0.00−0.31 to 0.31    
Constant 0.31−0.29 to 0.91 0.09−0.12 to 0.29 

In the multivariate meta-regression analysis, the effects of two predictors became significant: studies in Europe had a higher pooled effect size (indicating superior effects of psychotherapy) than studies in other parts of the world, and pharmacotherapy was significantly more efficacious in studies among specific target groups (such as older adults and patients who also had a general medical disorder) than in those among adults in general.

We also conducted a (manual) back-step meta-regression analysis. In this analysis, we dropped the least significant variable in each step, until only significant predictors (p<0.05) were retained in the model (Table 3). In this parsimonious model, we found that the same predictors were significant as in the full meta-regression model.

DISCUSSION

In this meta-analysis, we found that the differences in effects between psychotherapy and antidepressant medication were small to non-existent for major depression, panic disorder and SAD. We also found evidence that pharmacotherapy was significantly more efficacious in dysthymia, and that psychotherapy was significantly more efficacious in OCD. Furthermore, pharmacotherapy was significantly more efficacious than non-directive counseling, and psychotherapy was significantly more efficacious than pharmacotherapy with TCAs. These associations remained significant when we controlled for other characteristics of the studies in multivariate meta-regression analysis, except for the differential effects in dysthymia, which were no longer significant. In these multivariate meta-regression analyses, we also found that psychotherapy was more efficacious in studies from Europe compared with those from other countries, and that pharmacotherapy was significantly more efficacious in studies among specific target groups than in those among adults in general.

The present results indicate that different kinds of antidepressants and psychotherapies have varying degrees of efficacy in treating depression and anxiety disorders. TCAs and non-directive counseling seemed to be less efficacious than the other treatments, although we found in an earlier meta-analysis that the lower effects of non-directive counseling may be caused in part by researcher allegiance [93]. The finding that psychotherapy is less efficacious than pharmacotherapy in dysthymia is in line with earlier meta-analytic research [94]. However, the number of studies is small and the difference was no longer statistically significant after adjusting for quality and other study characteristics. As such, the finding is not very stable and more research is needed to examine this issue.

In OCD, the outcomes are rather straightforward in that psychotherapy is clearly more efficacious than antidepressants, even adjusting for quality and other characteristics of the studies. This is the first meta-analysis to show that psychotherapy is more efficacious than pharmacotherapy. This finding is also important from a clinical perspective, because OCD is often regarded as the most severe anxiety disorder.

One of the strengths of this study is the broad range of disorders and treatments we included. But the study also has some limitations. First, for several disorders insufficient numbers of studies were available. We only had a few studies examining PTSD, GAD and dysthymia. Second, the quality of many of the included studies was not optimal. Third, because of the many differences between the studies, we only examined the differential effects of psychotherapy and pharmacotherapy at post-test, and did not look at the longer-term effects. There are indications that psychotherapy may have sustained effects over the longer-term, while antidepressants do not have strong effects when the patients stop taking them [95]. Fourth, we only considered the effects of treatments on the disorders they were designed to address. Finally, while it is well known that pharmacotherapies have several side effects, which are often reported in the studies, the idea that psychotherapies can have negative effects has only recently been recognized [96], and these negative effects are typically not reported in the studies. It was, therefore, not possible to compare psychotherapies and pharmacotherapies in terms of negative effects.

Despite the limitations, we can conclude that pharmacotherapy and psychotherapy have comparable effects in several depressive and anxiety disorders, but this is not true for all disorders, especially not for OCD and possibly dysthymia. Furthermore, most psychotherapies and pharmacotherapies are equally efficacious, but this again is not true for all treatments, especially for TCAs and non-directive supportive counseling. Finally, while treatments may be equal in effects, they may not be equal in terms of patient preferences and costs, which deserve further investigations across disorders.

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