Canter PH, Ernst E (November 2003). "The cumulative effects of Transcendental Meditation on cognitive function--a systematic review of randomised controlled trials".Wien. Klin. Wochenschr. 115 (21–22): 758–66. doi:10.1007/BF03040500.PMID 14743579. "All 4 positive trials recruited subjects from among people favourably predisposed towards TM, and used passive control procedures … The association observed between positive outcome, subject selection procedure and control procedure suggests that the large positive effects reported in 4 trials result from an expectation effect. The claim that TM has a specific and cumulative effect on cognitive function is not supported by the evidence from randomized controlled trials."
Krisanaprakornkit, T.; Ngamjarus, C.; Witoonchart, C.; Piyavhatkul, N. (2010). "Meditation therapies for attention-deficit/hyperactivity disorder (ADHD)". In Krisanaprakornkit, Thawatchai. Cochrane Database Syst Rev 6 (6): CD006507.doi:10.1002/14651858.CD006507.pub2. PMID 20556767. "As a result of the limited number of included studies, the small sample sizes and the high risk of bias, we are unable to draw any conclusions regarding the effectiveness of meditation therapy for ADHD."
