There is a high need for evidence-based psychosocial treatments for adult attention-deficit hyperactivity disorder (ADHD) to offer alongside treatment as usual (TAU). Mindfulness-based cognitive therapy (MBCT) is a promising psychosocial treatment. This trial investigated the efficacy of MBCT + TAU v. TAU in reducing core symptoms in adults with ADHD.

A multicentre, single-blind, randomised controlled trial (ClinicalTrials.gov: NCT02463396). Participants were randomly assigned to MBCT + TAU (n = 60), an 8-weekly group therapy including meditation exercises, psychoeducation and group discussions, or TAU only (n = 60), which reflected usual treatment in the Netherlands and included pharmacotherapy and/or psychoeducation. Primary outcome was ADHD symptoms rated by blinded clinicians. Secondary outcomes included self-reported ADHD symptoms, executive functioning, mindfulness skills, self-compassion, positive mental health and general functioning. Outcomes were assessed at baseline, post-treatment, 3- and 6-month follow-up. Post-treatment effects at group and individual level, and follow-up effects were examined.

In MBCT + TAU patients, a significant reduction of clinician-rated ADHD symptoms was found at post-treatment [M difference = −3.44 (−5.75, −1.11), p = 0.004, d = 0.41]. This effect was maintained until 6-month follow-up. More MBCT + TAU (27%) than TAU participants (4%) showed a ⩽30% reduction of ADHD symptoms (p = 0.001). MBCT + TAU patients compared with TAU patients also reported significant improvements in ADHD symptoms, mindfulness skills, self-compassion and positive mental health at post-treatment, which were maintained until 6-month follow-up. Although patients in MBCT + TAU compared with TAU reported no improvement in executive functioning at post-treatment, they did report improvement at 6-month follow-up.

MBCT might be a valuable treatment option alongside TAU for adult ADHD aimed at alleviating symptoms.

Mindfulness-based cognitive therapy (MBCT) and maintenance antidepressant medication (mADM) both reduce the risk of relapse in recurrent depression, but their combination has not been studied.

To investigate whether MBCT with discontinuation of mADM is non-inferior to MBCT+mADM.

A multicentre randomised controlled non-inferiority trial (ClinicalTrials.gov: NCT00928980). Adults with recurrent depression in remission, using mADM for 6 months or longer (n = 249), were randomly allocated to either discontinue (n = 128) or continue (n = 121) mADM after MBCT. The primary outcome was depressive relapse/recurrence within 15 months. A confidence interval approach with a margin of 25% was used to test non-inferiority. Key secondary outcomes were time to relapse/recurrence and depression severity.

The difference in relapse/recurrence rates exceeded the non-inferiority margin and time to relapse/recurrence was significantly shorter after discontinuation of mADM. There were only minor differences in depression severity.

Our findings suggest an increased risk of relapse/recurrence in patients withdrawing from mADM after MBCT.