Schoenberg 2014.

Methods	Randomised controlled trial
Participants	Country: the Netherlands Setting: ambulatory Age: adults (18 to 65 years old) Sample size: 44 Sex: 23 women, 21 men Inclusion criteria: primary diagnosis of ADHD, DSM‐IV‐TR confirmed by 3 psychiatrists Exclusion criteria: substance abuse/dependence within the last 6 months; co‐morbid psychotic‐, borderline‐, antisocial‐, and behavioural disorders; and learning difficulties
Interventions	Intervention: mindfulness‐based cognitive therapy (12 weekly sessions) (n = 24; 15 participants with pharmacotherapy and 9 without pharmacotherapy). Control: waiting list group (n = 20; 16 participants with pharmacotherapy and 4 without pharmacotherapy) Dosage, timing of dosage and administration of pharmacotherapy were not specified.
Outcomes	Primary outcome ADHD symptoms ‐ Conners' Adult ADHD Selfrating Scale (CAARS: SV)
Notes	We contacted authors to get more information, but they had not responded at the time of writing. Study start date: not specified Study end date: not specified Funding source: this research was supported by BrainGain SmartMix Programme of the Netherlands Ministry of Economic Affairs and Netherlands Ministry of Education, Culture and Science. Declarations of interest: all authors declare that they have no conflicts of interest related to this work.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Comment: a random number table was used – whether the number was even or odd would dictate allocation to MBCT or WL.
Allocation concealment (selection bias)	Low risk	Comment: this procedure was carried out by a member of staff unrelated to the data collection, and was witnessed by the data manager of the project.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: it is not possible to blind personnel in a psychosocial intervention.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Comment: the outcomes were potentially prone to risk of bias without blinding of the assessor.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: of the remaining 44 participants, complete clinical data sets were not available for 2 (1 MBCT, 1 WL); in 1 case the baseline, the other the post‐treatment, questionnaires were not completed at the time of testing due to practical/time constraints.
Selective reporting (reporting bias)	Low risk	Comment: the study authors reported all proposed outcomes.
Other bias	Low risk	Comment: there was no evidence of other bias.
Conflict of interest	Low risk	Comment: no evidence of conflicts of interest