The Efficacy of CBT Treatment for Depression
The plethora of studies evaluating the efficacy and effectiveness of CBT (Cognitive Behaviour Therapy) over the last few decades has shown generally solid results for CBT as a treatment for depression (and many other disorders) with different groups, in different modes of delivery, and in manifold settings. There is no controversy on one fundamental finding: there is a vast amount of evidence showing that CBT is effective for depression. In this article we examine the different findings with respect to aspects such as client preference, mode of delivery of treatment, and comparisons between CBT and other treatment modalities, including antidepressant medication.
The clients like it
CBT is an acceptable treatment modality. A meta-analytic study by McHugh, Whitton, Peckham, Welge, & Otto (2013) identified 644 articles assessing adult patient preferences for the treatment of psychiatric disorders; in order to be included in the meta-analytic investigation, the studies had to include at least one psychological treatment and one pharmacologic treatment. Of the 34 studies which met inclusion criteria, there was a three-fold preference for psychological treatment. That is, the proportion of adult patients preferring psychological treatment was 0.75 (95% CI, 0.69–0.80), which was significantly higher than equivalent preference (i.e., higher than 0.50; P < .001). The authors noted that, given the mounting evidence for enhanced outcomes when clients are allowed to receive preferred psychiatric treatment, strategies should be developed to maximise the linkage of clients to their preferred treatment.
Definitely better than nothing
In meta-analysis examining treatment outcomes of CBT, the intervention yielded large effect sizes for the treatment of depression (Butler, Chapman, Forman, & Beck, 2006). Moreover, several meta-analyses have demonstrated that CBT was significantly more effective than untreated controls, waiting list clients, or those receiving no treatment (Dobson, 1989; Gloaguen, Cottraux, Cucherat, & Blackburn, 1998; Wilson, Mottram, & Vassilas, 2008).
Comparable to other treatments, and just as efficacious
CBT has been compared myriad times with other treatments, including both other psychotherapies and also medications. A study of seven trials randomising 741 participants to treatment of either CBT or interpersonal therapy reported at the end of treatment that:
- The four trials reporting data on the Hamilton Rating Scale for Depression showed no significant difference between the two interventions;
- The five trials reporting on the Beck Depression Inventory showed comparable results (Jakobsen, Hansen, Simonsen, Simonsen, & Gluud, 2012).
Braun, Gregory, & Ulrich (2013) applied two different meta-analytical techniques to 53 studies (3,965 patients) which directly compared two or more bona fide psychotherapies in a randomised trial. Meta-analyses conducted at the end of treatment on five different types of outcome measures directly compared each of the following therapies: CBT, behaviour activation therapy, psychodynamic therapy, interpersonal therapy, and supportive therapies, to all other treatments. Results showed that the treatments were equally efficacious except for the supportive therapies, which were somewhat less efficacious than the other treatments. CBT was superior in studies where therapy sessions lasted 90 minutes or longer; behavior activation therapy was more efficacious when therapy sessions lasted less than 90 minutes (Braun et al, 2013).
CBT, reminiscence therapy, and general psychotherapy were compared for effectiveness in treating depression in a meta-analysis of fourteen international studies of adults 55 or over. All three types of psychotherapy were found to be effective treatments for depression in older patients. Specifically, each individual therapy format was significantly more effective than placebo or no intervention, with CBT and reminiscence therapy having similar efficacy (Peng, Huang, Chen, & Zu, (2009).
Meta-reviews by Haby, Donnelly, Corry, & Vos (2006: 33 studies) and Beltman, Voshaar, and Speckens (2010: 29 studies, see details below) also supported the effectiveness of CBT. The Haby et al investigation concluded that CBT is overall an effective treatment for not only depression, but also panic disorder, and generalised anxiety disorder.
Different delivery formats deliver
The developed world, at least, is experiencing a current and projected shortage of therapists available to offer mental health services, yet as the United Kingdom’s Lord Layard observed in a speech, Britain’s biggest social problem is mental health. He suggested that Britain alone needs an additional 10,000 therapists delivering 10 sessions of CBT to 1,000,000 individuals each year (Sainsbury Centre for Mental Health, 2005, in White, 2008). Accordingly, many mental health experts are looking for alternative delivery formats to the tried-and-true, one-on-one mode of individual therapy, and some researchers have begun to test delivery modes such as computerised, group, and self-help CBT.
A meta-review of computerised CBT
Computer-mediated CBT has the capacity to deliver structured input consistently with precision. Observing that it also offers low-cost, easily accessible, flexible therapy in a non-stigmatising environment, one study conducted an analysis of reviews of efficacy of “cCBT” (computerised CBT) published between 1999 and February, 2011. The search yielded 12 systematic reviews from ten studies covering depression. The meta-review concluded that the limited evidence available supported the efficaciousness of MoodGYM, Beating the Blues, and Colour Your Life, although it also stated that it was not possible to discern the relative effectiveness of one package over the other (Foroushani, Schneider, & Assareh, 2011).
The SAMHSA studies: Computer CBT and guided self-help
In a similar vein, a number of studies listed on the United States Department of Health and Human Services SAMHSA National Registry of Evidence-based Programs and Practices consistently supports the finding of effectiveness of CBT either as a computerised CBT package (with or without minimal therapist help) or as an independent, guided self-help program.
A meta-analysis (of four United States and other-national studies) of depressed adults, with or without anxiety, examined the effectiveness of computerised cognitive behavioral therapy (cCBT) for the treatment of mild to moderate depression. It found improvement in psychological symptoms, depression symptoms, interpersonal and social functioning, quality of life, and participant satisfaction both with treatment and site of delivery (Kaltenthaler, Parry, Beverley, & Ferriter, 2008). In a similar review, a meta-analysis of 12 studies using randomised controlled trials to study internet-based CBT for symptoms of anxiety and depression found that, where therapist support was available, there was a large effect size. In the studies without therapist support, there was also an effect, but the size of it was smaller. The authors suggested that the effectiveness of the interventions was greatly enhanced by the addition of therapist support, but concluded that internet-based interventions are, overall, effective in the treatment of depression and anxiety symptoms (Spek, Cuijpers, Nyklicek, Riper, Keyzer, & Pop, 2007).
Finally of the computer-based studies, a 19-study meta-review by Reger & Gahm (2009) of computer-based CBT treatments for anxiety showed that not only symptoms of anxiety, but also those of depression, general distress, and dysfunctional thinking were relieved post-treatment. General functioning and quality life were improved. The studies, both in the United States and internationally, were conducted between 2000 and 2007, but the authors advised caution in interpreting results, as there were few placebo-controlled studies available and many of the studies had small sample sizes and high dropout rates.
As with computer-based CBT, the effectiveness of CBT guided self-help for anxiety and depression is not well established. One meta-analysis reported on the results of 13 studies of adults, aged 17 to 64, who used guided self-help CBT materials. The studies, conducted between 2003 and 2009 in the United States and other nations, evaluated the effectiveness of randomised, controlled trials of CBT for anxiety and depression. But while clinician and self-report measures found that depressive and anxiety symptoms had substantially reduced, researchers were able to draw only limited conclusions. This was because recruitment methods for the studies differed significantly (self-selected versus referral), many of the studies only partially addressed the issue of fidelity, and amount of therapist help varied widely: between 30 minutes and three hours (Coull & Morris, 2011).
The meta-study by Beltman et al (2010: referred to above) examined 29 studies in the United States and other nations occurring between 1984 and 2008 which investigated the effectiveness of CBT for depression in people with a diversity of somatic diseases (such as cancer, HIV infection, multiple sclerosis, or renal failure). Participants were diagnosed as having depressive symptoms or depressive order as well as the somatic disease. CBT, administered in individual or group sessions, was compared to wait list or treatment as usual. CBT was significantly more effective at reducing both depressive symptoms and depressive disorder than control, with CBT for depressive disorder yielding a larger effect size than for depressive symptoms. The results also suggested that, while individual treatment might be more effective than group therapy in somatically ill people with depressive disorder, group therapy also reduces symptoms. Overall, CBT is effective in treating depressive symptoms in people with a variety of somatic diseases.
Similar findings were obtained from a meta-review of twenty-three studies. Analysis of group CBT versus usual care alone (14 of the studies) showed a significant effect in favour of group CBT immediately post-treatment, with some evidence of benefit maintained at both short term and also medium- to long-term follow-up. Seven of the studies examined group versus individually-delivered CBT; these showed a moderate treatment effect in favour of individually-delivered CBT right after treatment, but no evidence of difference at either short- or medium- to long-term follow-up. Thus, group CBT helps depressed individuals more than usual care, and seems to be no less effective than individual CBT after three months (Huntley, Araya, & Salisbury, 2012).
And CBT is as good as antidepressant medication
One study is particularly noteworthy regarding the question of whether CBT or antidepressant medication helps clients more. The background is that antidepressant medication prevents the return of depression symptoms, but only as long as the medication is continued. The study, by Hollon et al (2005), sought to determine whether cognitive therapy has an enduring effect and to compare this effect against the effect produced by continued antidepressant medication. In outpatient clinics, patients who responded to CBT in a randomised controlled trial were withdrawn from treatment and compared during a 12-month period with medication responders who had been randomly assigned to either continuation medication or placebo withdrawal.
Patients who survived the continuation phase without relapse were withdrawn from all treatment and observed across a subsequent 12-month naturalistic follow-up. Patients had initially been selected to represent those with moderate to severe depression. The 104 patients who responded to treatment (nearly 60 percent of those initially assigned) were enrolled in the continuation phase. Those withdrawn from CBT were allowed up to three booster sessions during continuation; those assigned to continuation medication were kept at full dosage levels. Results showed that those withdrawn from CBT were significantly less likely to relapse during continuation than patients withdrawn from medications (30.8 percent versus 76.2 percent; P = .004) and no more likely to relapse than patients who kept taking continuation medication (30.8 percent versus 47.2 percent; P = 20). The researchers concluded that CBT has an enduring effect extending beyond the end of treatment, seemingly as effective as keeping patients on medication (Hollon et al, 2005).
The Hollon et al study is in line with results from a study by DeRubeis et al (2005, in Otto, 2013), in which 58 per cent of those on CBT and 58 percent of those given antidepressant medication for severe depression were responding to treatments at the 16-week mark. Otto (2013) also reported on a meta-analysis of acute phase treatment, in which either CBT or antidepressant medications were administered (seven studies). Upon discontinuation, those in the CBT group were associated with a 61 percent lower relapse/recurrence rate of the depression. In six studies, CBT was administered as an addition to medication. Adding in the CBT resulted in a 61 percent lower relapse/recurrence rate (Vittengl et al, 2009, in Otto, 2013).
In summary, the answer to the question of why we should employ CBT to treat depression is because it is proven efficacious: far superior to wait list, supportive “treatment as usual”, and controls, and at least as effective as other therapies and antidepressant medication, with more enduring effects than medication. It seems to be most potent delivered in standard one-on-one format, but even in group, computerised, or self-help format, it still reduces depressive symptoms. And clients would far rather do a course of CBT than pop anti-depression pills.
Is there anyone who shouldn’t be treated with CBT? The contraindications
CBT has been used clinically with almost every imaginable client population. Few evidence-based exclusion criteria for the use of CBT with specific disorders have been established. Researchers suspect, however, that many studies of CBT typically exclude certain conditions due to beliefs that these could lead to less improvement in symptoms over the course of treatment. To include individuals possessing such characteristics in a study might be to skew negatively the results, making CBT look less effective than it is with suitable clients; beyond that, such clients may be poorly served by beginning a therapy which can ultimately not achieve measurable results for them.
Typical exclusion criteria consist of comorbid alcohol or other substance disorders, some psychotic disorders, organic brain syndrome, and learning difficulties, with many studies also specifying that participants who have depression not be at risk of suicide. More research on this issue is needed; many believe that individuals with these conditions may still benefit from CBT (Halverson, Bienenfeld, Leonard, & Riemann, 2014). Beyond the question of inclusion in research studies, there is the matter of whether the depressed clients of a clinician not participating in a study may find CBT useful even though the clients’ other issues may cause a smaller effect.
This article was adapted from the Mental Health Academy CPD course “Using CBT with Depression”.
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