Mindfulness has been defined as “intentionally directing attention to present moment experiences with an attitude of curiosity and acceptance.” Mindfulness-based interventions (MBIs) aim to improve mindfulness skills.

A newly-published meta-analysis of randomized controlled trials (RCTs) by a team of British neurologists and psychiatrists explores the effectiveness of MBIs in treating a variety of mental health conditions in children and adolescents. Among those conditions is the attention deficit component of ADHD.

A comprehensive literature search identified studies that met the following criteria:

1. The effects of mindfulness were compared against a control condition – either no contact, waitlist, active, or attention placebo. Waitlist means the control group receives the same treatment after the study concludes. Active control means that a known, effective treatment (as opposed to a placebo) is compared to an experimental treatment. Attention placebo means that controls receive a treatment that mimics the time and attention received by the treatment group but is believed not to have a specific effect upon the subjects. Participants were randomly assigned to the control condition.
2. The MBI was delivered in more than one session by a trained mindfulness teacher, involved sustained meditation practice, and it was not mixed in with another activity such as yoga.

Eight studies evaluating attention deficit symptoms, with a combined total of 1,158 participants, met inclusion criteria. The standardized mean difference (SMD) was 0.19, with a 95% confidence range of 0.04 to 0.34 (p = .02). That indicates a small effect size for MBIs in reducing attention deficit symptoms. Heterogeneity was low (I2 = 35, p = .15), and the Egger test showed little sign of publication bias (p = 0.42).

When looking only at studies with active controls, five studies with a total of 787 participants yielded an SMD of 0.13, with a 95% confidence interval of -0.01 to 0.28 (p = .06), indicating a tiny effect size that failed to reach significance. Active controls most commonly received health education, with a few receiving social responsibility trainings or Hatha yoga.

Overall, this meta-analysis suggests limited effectiveness, especially when compared with active controls. If MBIs are effective for ADHD, there effect on symptoms is very small. Thus, such treatments should not be used in place of the many well-validated, evidenced-based therapies available. Whether longer periods of MBI (training times varied between 2 and 18 hours spread out over 2 to 24 weeks) might result in greater effect sizes remains unexplored.

REFERENCES
Darren L. Dunning, Kirsty Griffiths, Willem Kuyken, Catherine Crane, Lucy Foulkes, Jenna Parker, and Tim Dalgleish, “Research Review: The effects of mindfulness-based interventions on cognition and mental health in children and adolescents – a meta-analysis of randomized controlled trials,” Journal of Child Psychology and Psychiatry (2018), doi:10.1111/jcpp.12980.