This is a plain English summary of an original research article
This review looked at how effective different psychological "talking" therapies were at preventing relapse of depression.
It found that cognitive behavioural therapy, mindfulness-based cognitive therapy and interpersonal psychotherapy all reduced the risk of depression relapse over a year by 20 to 25% compared with a control treatment. There was further evidence that the effect for cognitive behavioural therapy was sustained up to two years.
This reinforces NICE guidance, which recommends that cognitive behavioural therapy or mindfulness-based cognitive therapy be offered to people at risk of a relapse of depression.
The trial results suggested factors like participant characteristics and treatment delivery affected treatment success. These results may help therapists further tailor their treatment approaches within the NHS Improving Access to Psychological Therapies programme.
Why was this study needed?
Around 8-12% of people in the UK experience depression every year. Roughly half of those will recover within 18 months. However, 60% of people who have experienced one episode of depression will experience symptoms again in the future, known as relapse. The risk of relapse increases the greater the number of previous depression episodes. The World Health Organization estimates that depression is the largest single cause of disability – a physical or mental impairment that affects someone’s ability to carry out everyday tasks – worldwide.
Reviews have compared different drugs for relapse prevention, but reviews of psychological "talking" therapies have focused on one therapy at a time. This systematic review aimed to address this, by comparing the effectiveness of several psychological or non-drug treatments specifically used to prevent depression relapse.
What did this study do?
This systematic review included 29 trials that randomised people not currently depressed – but who were at risk of relapse – to receive various forms of psychological therapy or a control (comparison) therapy, such as continuing drug treatment or monitoring without an "active" treatment. The review did not provide a head to head comparison between psychological therapy and continuing medication. Relapse was defined as changing from being fully or partially recovered to being depressed, measured using accepted diagnostic criteria. The results of 22 of the studies (including 4,216 people) were pooled in a meta-analysis. Most studies looked at specific types of therapies – cognitive behavioural therapy (CBT, 10 studies), mindfulness-based cognitive therapy (MBCT, seven studies) and interpersonal psychotherapy (IPT, four studies) – see Definitions. Four studies investigated "service-led" programmes, for example involving visits or calls with a GP-based specialist.
What did it find?
- At 12 months the differences in effectiveness between the therapies were not statistically significant. People who received CBT were 25% less likely to relapse, 21% for MBCT, and 22% for IPT, compared with controls.
- Service-led programmes did not reduce the risk of relapse at 12 months compared with control either (RR 1.00, 95% CI 0.81 to 1.23).
- A similar risk reduction was found for CBT at 24 months (RR 0.72, 95% confidence interval [CI] 0.57 to 0.91) and at 12 months (RR 0.75, CI 0.64 to 0.89). However, this was based on data from seven studies, and variations between the methods and findings mean that other factors may be influencing results.
- Data from six studies did not find that the effects of IPT at 12 months (RR 0.78, 95% CI 0.65 to 0.95) were sustained at 24 months (RR 0.92, 95% CI 0.81 to 1.05). No other studies reported results at 24 months.
What does current guidance say on this issue?
The 2009 NICE depression guideline recommends individual cognitive behavioural therapy or group mindfulness-based cognitive therapy for people at high risk of relapse. This includes people who have relapsed despite continued antidepressant treatment, who are either unable or unwilling to continue antidepressant treatment, or who still have some symptoms. NICE recommends 16-20 sessions of CBT delivered over three to four months, or weekly two-hour sessions of MBCT in groups of 8-15 delivered over eight weeks, with four follow-up sessions in the 12 months after the treatment ends.
The Improving Access to Psychological Therapies (IAPT) programme is a large-scale initiative that aims to greatly increase the availability of NICE recommended psychological treatment for common mental health problems, including depression.
What are the implications?
This review identified three psychological therapies that prevented depression relapse better than control treatments. There was a lot of variation between studies, which means that we cannot be completely certain that the results were due to the treatment rather than the influence of other factors. For example, participants varied in the number of previous episodes of depression they had, and in the treatments they had previously received. There was variation in the treatment that was used as a comparison and the "intensity" of the psychological therapy – the number of sessions, and over how many weeks it was delivered. The relevance to the UK setting is not clear as the intensity of the psychological therapy used in many of the studies differed from NICE recommendations. This was a thorough review, but the evidence was generally of poor quality which limits the authority of findings.
The cost-effectiveness of psychological therapy was not assessed. The authors speculate that it may be more cost-effective to deliver a psychological therapy if the effect lasts for up to two years, rather than prescribing antidepressants for that entire time to achieve a similar effect. For now, the confirmation that therapies provided as part of the NHS funded IAPT programme have proven useful adds support to efforts to make this programme more widely accessible.
This review did not provide direct comparison of psychological therapy with continued medication for people at risk of further depression. The authors noted that it was difficult to establish the different levels of medication use in the included trials. A large NIHR funded trial published recently (see also this Signal) was able to compare this directly in an NHS context and found that psychological therapies and continuing medication were equally effective. This single study will be added to future reviews to strengthen our evidence base for the future.
Clarke K, Mayo-Wilson E, Kenny J et al. Can non-pharmacological interventions prevent relapse in adults who have recovered from depression? A systematic review and meta-analysis of randomised controlled trials. Clin Psychol Rev. 2015;39:58-70.
iCope. Interpersonal therapy (IPT). London: Camden and Islington Psychological Therapies Service.
NICE. Depression in adults: the treatment and management of depression in adults. CG90. London: National Institute for Health and Care Excellence; 2009.
Mental Health Foundation. Mental health statistics: the most common mental health problems. London: Mental Health Foundation.
NHS Choices. Cognitive behavioural therapy (CBT). London: NHS Choices; 2014.
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