Dutch RCT of mindfulness therapy vs methylphenidate in ADHD Meppelink et al. (2016) note that


  The effectiveness of mindfulness training for children
  and adolescents with ADHD has been demonstrated
  by a number of studies; however, research in
  this field is limited by a lack of randomised controlled
  clinical trials with large samples, standardised formats
  of mindfulness training and objective measures.
  Further assessment of mindfulness training for childhood
  ADHD is, therefore, needed. A randomised controlled
  trial, which compares mindfulness training for
  ADHD with methylphenidate, is currently being conducted
  in the Netherlands.


Has this resulting study been published since then?
This is the protocol study referred to:

https://bmcpsychiatry.biomedcentral.com/track/pdf/10.1186/s12888-016-0978-3

The trial only remained in a planned state:

http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4206

For people interested in mindfulness in ADHD I would like to mention the main evidences (I HAVE ORDINATED BY DATE):

Zylowska, L., Ackerman, D., Yang, M., Futrell, J., Horton, N., &amp; Hale, T. et al. (2007). Mindfulness Meditation
Training in Adults and Adolescents With ADHD: A Feasibility Study. Journal Of Attention Disorders, 11,
737-746.

Smalley, S. L., Loo, S. K., Hale, T., Shrestha, A., McGough, J., Flook, L., &amp; Reise, S. (2009). Mindfulness and attention deficit hyperactivity
disorder. Journal of Clinical Psychology, 65(10), 1087-1098.

Singh, N. N., Singh, A. N., Lancioni, G. E., Singh, J., Winton, A. S., W., &amp; Adkins, A. D. (2010). Mindfulness training for parents and their children
with ADHD increases the children's compliance. Journal of Child and Family Studies, 19(2), 157-166.

van de Weijer-Bergsma, E., Formsma, A., de Bruin, E., &amp; Bögels, S. (2011). The Effectiveness of Mindfulness
Training on Behavioral Problems and Attentional Functioning in Adolescents with ADHD. Journal Of
Child And Family Studies, 21, 775-787.

van der Oord, S., Bögels, S., &amp; Peijnenburg, D. (2011). The Effectiveness of Mindfulness Training for Children with
ADHD and Mindful Parenting for their Parents. Journal Of Child And Family Studies, 21, 139-147.

Carboni, J. A., Roach, A. T., &amp; Fredrick, L. D. (2013). Impact of mindfulness training on the behavior of elementary students with attentiondeficit/
hyperactive disorder. Research in Human Development, 10(3), 234-251.

Mitchell, J., McIntyre, E., English, J., Dennis, M., Beckham, J., &amp; Kollins, S. (2013). A Pilot Trial of Mindfulness
Meditation Training for ADHD in Adulthood: Impact on Core Symptoms, Executive Functioning, and
Emotion Dysregulation. Journal Of Attention Disorders.

Edel, M., Holter, T., Wassink, K., &amp; Juckel, G. (2014). A Comparison of Mindfulness- Based Group Training and
Skills Group Training in Adults With ADHD: An Open Study. Journal Of Attention Disorders.

Schoenberg, P., Hepark, S., Kan, C., Barendregt, H., Buitelaar, J., &amp; Speckens, A. (2014). Effects of mindfulnessbased
cognitive therapy on neurophysiological correlates of performance monitoring in adult attentiondeficit/
hyperactivity disorder. Clinical Neurophysiology, 125, 1407-1416.

Bueno, V., Kozasa, E., da Silva, M., Alves, T., Louzã, M., &amp; Pompéia, S. (2015). Mindfulness Meditation Improves
Mood, Quality of Life, and Attention in Adults with Attention Deficit Hyperactivity Disorder. Biomed
Research International, 2015, 1-14. doi:10.1155/2015/962857

Haydicky, J., Shecter, C., Wiener, J., &amp; Ducharme, J. M. (2015). Evaluation of MBCT for adolescents with ADHD and their parents: Impact on
individual and family functioning. Journal of Child and Family Studies, 24(1), 76-94.

Janssen, L., Kan, C. C., Carpentier, P. J., Sizoo, B., Hepark, S., Grutters, J., &amp; Speckens, A. E. (2015). Mindfulness based cognitive therapy
versus treatment as usual in adults with attention deficit hyperactivity disorder (ADHD). BMC Psychiatry, 15(1), 216.

Lo, H. H., Wong, S. Y., Wong, J. Y., Wong, S. W., &amp; Yeung, J. W. (2016). The effect of a family-based mindfulness intervention on children with
attention deficit and hyperactivity symptoms and their parents: design and rationale for a randomized, controlled clinical trial (Study
protocol). BMC Psychiatry, 16(1), 65.