To the Editor We read with interest the article by McCarthy and colleagues1 in the December 2013 issue of JAMA Psychiatry investigating the attention-deficit/hyperactivity disorder (ADHD)–related differences in resting-state functional connectivity (RSFC) between adults with ADHD and healthy controls. McCarthy et al reported decreased RSFC within attention networks and increased RSFC within the affective default mode and cognitive control networks in patients with ADHD. However, they had a small sample size and even quite heterogeneous patients, with 10 patients (63%) who had a long history of methylphenidate drug treatment, 4 (25%) who withheld their stimulant medications for 48 hours, and only 2 patients who were treatment naive, negating that numerous studies have shown significant effects of methylphenidate on brain function in ADHD.
Qi R, Zhang LJ, Lu GM. Emphasize the Effect of Methylphenidate on Brain Function in Attention-Deficit/Hyperactivity Disorder Research. JAMA Psychiatry. 2014;71(2):210. doi:10.1001/jamapsychiatry.2013.4107