CBT is arguably the most widely studied form of psychotherapy. We identified 269 meta-analytic reviews that examined CBT for a variety of problems, including substance use disorder, schizophrenia and other psychotic disorders, depression and dysthymia, bipolar disorder, anxiety disorders, somatoform disorders, eating disorders, insomnia, personality disorders, anger and aggression, criminal behaviors, general stress, distress due to general medical conditions, chronic pain and fatigue, distress related to pregnancy complications and female hormonal conditions. Additional meta-analytic reviews examined the efficacy of CBT for various problems in children and elderly adults. The vast majority of studies (84%) was published after 2004, which was the last year of coverage of the review by Butler and colleagues (2006), making the present study the most comprehensive and contemporary review of meta-analytic studies of CBT to date.
For the treatment of addiction and substance use disorder, the effect sizes of CBT ranged from small to medium, depending on the type of the substance of abuse. CBT was highly effective for treating cannabis and nicotine dependence, but less effective for treating opioid and alcohol dependence. For treating schizophrenia and other psychotic disorders, the empirical literature suggested appreciable efficacy of CBT particularly for positive symptoms and secondary outcomes in the psychotic disorders, but lesser efficacy than other treatments (e.g. family intervention or psychopharmacology) for chronic symptoms or relapse prevention.
The meta-analytic literature on the efficacy of CBT for depression and dysthymia was mixed with some studies suggesting strong evidence and others reporting weak support. Some authors have suggested that the strong effects in some studies may be an overestimation due to a publication bias (Cuijpers, et al., 2010). Similarly, the efficacy of CBT for bipolar disorder was small to medium in the short-term in comparison to treatment as usual. However, there was limited evidence for the superiority of CBT alone over pharmacological approaches; for the treatment of depressive symptoms in bipolar disorder, the use of CBT was well supported. However, the long-term superiority compared to other treatments is still uncertain.
The efficacy of CBT for anxiety disorders was consistently strong, despite some notable heterogeneity in the specific anxiety pathology, comparison conditions, follow-up data, and severity level. Large effect sizes were reported for the treatment of obsessive compulsive disorder, and at least medium effect sizes for social anxiety disorder, panic disorder, and post-traumatic stress disorder. Medium to large CBT treatment effects were reported for somatoform disorders, such as hypochondriasis and body dysmorphic disorder. However, more studies using larger trials and greater sample sizes are needed to draw more conclusive findings with regard to CBT’s relative efficacy in comparison to other active treatments.
For the treatment of bulimia, CBT was considerably more effective than other forms of psychotherapies, but less is known for other eating disorders. Similarly, CBT demonstrated superior efficacy as compared to other interventions for treating insomnia when examining sleep quality, total sleep time, waking time, and sleep efficiency outcomes. However, although there were small effects of CBT for sleep problems among older adults (aged 60+), these effects may not be long lasting (Montgomery & Dennis, 2009).
For personality disorders, there was some evidence for superior efficacy of CBT as compared to other psychosocial treatments for the personality disorders. However, the studies showed considerable variation in measurement methods, comorbid disorders, and demographic variables. CBT also produced medium to large effect sizes for treating anger and aggression (e.g., Saini, 2009), although a greater number of well-controlled studies are needed to more adequately parse out the specific efficacy of CBT compared to the psychosocial treatments for anger on the whole. Similarly, more studies are needed before any firm conclusions can be drawn about the efficacy of this treatment for criminal behaviors.
As a stress management intervention, CBT was more effective that other treatments, such as organization-focused therapies. However, more research on the long-term effects of CBT for occupational stress is needed. Furthermore, there are open questions about the relative efficacy of CBT versus pharmacological approaches to stress management. Similarly, several common concerns recurred across meta-analytic examinations of CBT for chronic medical conditions, chronic fatigue and chronic pain, namely: (1) a scarcity of studies and small sample sizes; (2) poor methodological design of studies that are included in meta-analyses; and (3) grouping of CBT with a host of other psychotherapies (such as psychodynamic therapy, hypnotherapy, mindfulness, relaxation, and supportive counseling), which made it difficult to parse out whether there are any superior effects of CBT in the majority of medical conditions examined.
There was preliminary evidence for CBT for treating distress related to pregnancy complications and female hormonal conditions. However, more research is needed due to a scarcity of follow-up data and low quality studies. This appeared to be a highly promising area for CBT given that the alternative – pharmacological treatments – can be associated with serious risks of adverse effects for pregnant women and breastfeeding mothers.
In our review of meta-analyses, CBT tailored to children showed robust support for treating internalizing disorders, with benefits outweighing pharmacological approaches in mood and anxiety symptoms. The evidence was more mixed for externalizing disorders, chronic pain, or problems following abuse. Moreover, there remains a need for a greater number of high-quality trials in demographically diverse samples. Similarly, CBT was moderately efficacious for the treatment of emotional symptoms in the elderly, but no conclusions about long-term outcomes of CBT or combination therapies consisting of CBT, and medication could be made.
Finally, our review identified 11 studies that compared response rates between CBT and other treatments or control conditions. In 7 of these reviews, CBT showed higher response rates than the comparison conditions, and in only one review (Leichsenring & Leibig, 2003), which was conducted by authors with a psychodynamic orientation, reported that CBT had lower response rates than comparison treatments.
In sum, our review of meta-analytic studies examining the efficacy of CBT demonstrated that this treatment has been used for a wide range of psychological problems. In general, the evidence-base of CBT is very strong, and especially for treating anxiety disorders. However, despite the enormous literature base, there is still a clear need for high-quality studies examining the efficacy of CBT. Furthermore, the efficacy of CBT is questionable for some problems, which suggests that further improvements in CBT strategies are still needed. In addition, many of the meta-analytic studies included studies with small sample sizes or inadequate control groups. Moreover, except for children and elderly populations, no meta-analytic studies of CBT have been reported on particular subgroups, such as ethnic minorities and low income samples.
Despite these weaknesses in some areas, it is clear that the evidence-base of CBT is enormous. Given the high cost-effectiveness of the intervention, it is surprising that many countries, including many developed nations, have not yet adopted CBT as the first-line intervention for mental disorders. A notable exception is the Improving Access to Psychological Therapies initiative by the National Health Commissioning in the United Kingdom (Rachman & Wilson, 2008). We believe that it is time that others follow suit.