Mindfulness-based cognitive therapy (MBCT) and mindfulness in general have been pretty hot topics in the woodland over the last couple of years. A growing number of reliable studies have been published that show the benefits of this approach for a wide range of mental health conditions.

We know that depression is a recurrent condition and that people who do not receive an effective ongoing treatment are at high risk of relapse. Antidepressants are a very effective maintenance treatment, but not everyone wants to take medication long-term and many of us find it difficult to live with the side effects.

Alternatives to drug treatment (individual CBT, interpersonal therapy, MBCT etc) are always in demand from service users with recurrent depression and these have been recommended by NICE for some years now.

New research published today in the Lancet suggests that MBCT might be a viable option for people at risk of depression relapse. The randomised controlled trial (RCT) conducted across 95 general practices throughout the South West of England suggests that MBCT could be a cost effective solution for large groups of patients.

Methods

Adult patients currently on a therapeutic dose of maintenance antidepressants, with 3 or more previous major depressive episodes, were recruited from primary care practices in both urban and rural settings (in Bristol and various locations across Devon).

Patients were excluded from the trial if they had a current major depressive episode, comorbid diagnoses of current substance misuse, organic brain damage, current or past psychosis (including bipolar disorder), persistent antisocial behaviour, persistent self-injury needing clinical management or therapy and formal concurrent psychotherapy.

Participants were randomly assigned (in a 1:1 ratio) to either:

1. MBCT-TS: An 8-week MBCT class (two and a quarter hours per class) that included support to taper or discontinue their maintenance antidepressants. Patients in this arm were given daily home practice and the option to attend 4 follow up sessions over a 12 month period
2. ADM: Continued antidepressant maintenance treatment

It was a single-blind trial because it was not possible to mask the study participants to the treatments they were receiving. Research assessors were masked to treatment allocation and the authors reported that the fidelity of this masking was moderate with “assessors correctly guessing allocation for 56% of assessments”.

The primary outcome was time to relapse or recurrence of depression, and patients were followed up at five separate intervals during the 2-year study (1 month, 9 months, 12 months, 18 months and 24 months).

Secondary outcomes were number of depression-free days, residual depressive symptoms, psychiatric and medical comorbidity, quality of life and cost-effectiveness.

The researchers used an intention to treat analysis.

The baseline characteristics of the study population were broadly similar across the two treatment arms. The participants were 99% white ethnic origin and mostly women. There were slightly more women in the ADM arm than the MBCT-TS arm (82% vs 71%), but the researchers state that “no evidence exists that patients’ gender moderates MBCT treatment outcome”. Do shout if you know of any.

Results

• The time to relapse or recurrence of depression over the 24 months was very similar between the two groups:
  • 44% of the MBCT-TS relapsed
  • 47% of the ADM group relapsed
  • Hazard ratio 0·89 (95% CI 0·67 to 1·18; p=0·43)
• There were 10 serious adverse events reported; 4 of which resulted in the death of the participant. These were evenly split across the two groups. The Trial Steering and Data Monitoring Committee concluded that none of the serious adverse events were related to the intervention or the trial.
• Treatment adherence was high:
  • 83% of people in the MBCT-TS group completed 4 or more sessions of MBCT
    • 71% of people who completed 4 or more sessions also discontinued their antidepressant use
  • 76% of people in the ADM group remained on a therapeutic dose
• Group MBCT compares quite favourably to individual antidepressant prescriptions on cost terms. Being a group intervention, it could potentially be rolled out to primary care practices and other settings:
  • Total health and social care cost per participant did not differ significantly between the MBCT-TS and the ADM group (mean difference £124, 95% CI -749·98 to 972·57, p=0·80)

Conclusions

The authors concluded:

We found no evidence that MBCT-TS is superior to maintenance antidepressant treatment for the prevention of depressive relapse in individuals at risk for depressive relapse or recurrence. Both treatments were associated with enduring positive outcomes in terms of relapse or recurrence, residual depressive symptoms, and quality of life.

This is an interesting way to present the results. Clearly a study that finds no significant difference between two treatments is not the same as a study that establishes equivalence.

The top-level result of this study (time to relapse or recurrence of depression over the 24 months) is not statistically significant (p=0.43), but what would the researchers have to do to provide evidence for a claim that MBCT is equally as good as maintenance antidepressant treatment?

Lesaffre (2008) suggests that “proving that two treatments are equal in performance is impossible with statistical tools”. Instead he suggests that equivalence trials must start by prospectively setting a clinically acceptable level of equivalence between two interventions. Something perhaps for a future study.

Strengths and limitations

Overall, this is a well conducted and nicely reported RCT, which finds a promising result for MBCT. The retention rates in the trial were high, as were the rates of treatment adherence. The 2 year follow-up was relatively long for a trial of this nature and this maximised the external validity.

The people included in this study were quite a specific population:

• At high risk of depressive relapse or recurrence
• Currently taking antidepressants
• Predominantly white and female
• Open to stopping their drug therapy and starting a group psychosocial treatment

As such, the results of this trial may only be applicable to a small proportion of the population.

The trial had a simple design, which is commendable, but the absence of a usual care or attention control group means that we can’t be sure that the effects of MBCT are specific to MBCT.

However, these results (and those of other recent studies) do suggest that psychosocial treatments such as MBCT and CBT may offer added value for patients who need them most (i.e. those at the highest risk of depressive relapse or recurrence). It will be interesting to see how this evidence is picked up by clinicians and commissioners, seeking to develop stratified approaches to preventing depression.

Links

Primary paper

Kuyken W. et al (2015) Effectiveness and cost-effectiveness of mindfulness-based cognitive therapy compared with maintenance antidepressant treatment in the prevention of depressive relapse or recurrence (PREVENT): a randomised controlled trial. The Lancet, published online 21 Apr 2015.

Other references

Tomlin A. (2012) Should we be offering mindfulness-based cognitive therapy to all patients with residual depressive symptoms? The Mental Elf, 3 Oct 2012.

Lesaffre E. (2008) Superiority, Equivalence, and Non-Inferiority Trials (PDF). Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):150-4