A Dutch study compared the efficacy of mindfulness-based cognitive therapy (MBCT) combined with treatment as usual (TAU), with TAU-only as the control group. MBCT consisted of an eight-week group therapy consisting of mindfulness exercises (bodyscan, sitting meditation, mindful movement), psychoeducation about ADHD, and group exercises. TAU consisted of usual treatment in the Netherlands, including medications and other psychological treatment. Sixty individuals were randomly assigned to each group. MBCT was taught in subgroups of 8 to 12 individuals. Patients assigned to TAU were not brought together in small groups. Baseline demographic and clinical characteristics were closely matched for both groups.

Outcomes were evaluated at the start, immediately following treatment, and again after 3 and 6 months using well-validated rating scales. Following treatment, the MBCT + TAU group outperformed the TAU group by an average of 3.4 points on the Conners’ Adult Rating Scale, corresponding to a standardized mean difference of .41. Thirty-one percent of the MBCT + TAU group made significant gains, versus 5% of the TAU group. 27% of MBCT +TAU patients scored a symptom reduction of at least 30 percent, as opposed to only 4% of TAU patients. Three and six-month follow-up effects were stable, with an effect size of .43.

The authors concluded “that MBCT has significant benefits to adults with ADHD up to 6 months after post-treatment, with regard to both ADHD symptoms and positive outcomes.” Yet in their section on limitations, they overlook a potentially important one. There was no active placebo control. Those who were undergoing TAU-only were aware that they were not doing anything different from what they had been doing before the study. Hence no substantial placebo response would be expected from this group during the intervention period (post-treatment they were offered an opportunity to undergo MBCT). Moreover, MBCT + TAU participants were gathered into small groups, whereas TAU participants were not. We therefore have no way of knowing what effect group interaction had on the outcomes, because it was not controlled for. So, although these results are intriguing and suggest that further research is worthwhile, the work is not sufficiently rigorous to definitively conclude that MBCT should be prescribed for adults with ADHD.

Note: This post was co-authored by Andrew Reding.

REFERENCES
Janssen L, Kan CC, Carpentier PJ, Sizoo B, Hepark S, Schellekens MPJ, Donders ART, Buitelaar JK, Speckens AEM. “Mindfulness-based cognitive therapy v. treatment as usual in adults with ADHD: a multicentre, single-blind, randomised controlled trial,” Psychological Medicine (2018), https:// doi.org/10.1017/S0033291718000429