On February 17, Lancet Psychiatry published a study that concluded MRI brain scans had shown that individuals with ADHD had smaller brains than normal, and that this proved that ADHD is a "disorder of the brain." The study generated media headlines around the world, such as this one in Newsweek:  “Study finds Brains of ADHD Sufferers Are Smaller.”

That conclusion is belied by the study's own data. In fact, the researchers found that the distribution of individual brain volumes in the ADHD and control groups almost entirely overlapped. This means that at an individual level, a person diagnosed with ADHD is almost as likely to have a brain volume above the normal "average" as to have a brain volume below that average. As such, the MRI data showed that brain volume size, on an individual level, is, in fact, not a distinguishing characteristic of ADHD. 

In addition, the researchers hid the most most important result in the appendix: The ADHD group scored higher on IQ tests than the controls. This directly contradicts the study's stated conclusion that ADHD is a "disorder of the brain."

We have published a detailed critique of this study on madinamerica.com. 

This study, unless it is retracted, will do great harm. It falsely informs children, teenagers, and adults diagnosed with ADHD that they have smaller brains than normal. This will change their sense of who they are, and lead them to believe that they suffer from a known brain abnormality. And as can be seen in the media headlines, it has already led to reports that have misinformed societies around the world  about what is “known” about ADHD. 

We urge you to join Mad in America Foundation, which is a non-profit webzine and continuing education organization, to petition Lancet Psychiatry to retract the study, and to inform the media of these two key points:

• That the “mega-analysis” of MRI scans showed that the brain volumes of individuals in both cohorts mostly overlapped, and thus does not provide evidence that individuals so diagnosed have smaller brains than normal.
• That the  ADHD cohort also scored higher on IQ tests.

We will submit this petition to Niall Boyce, M.D., who is the founding editor of Lancet Psychiatry.