[Skeptical review of the state of neuroimaging in attention deficit hyperactivity disorder]

Attention-deficit/hyperactivity disorder (ADHD) has been the focus of magnetic resonance imaging studies for more than 30 years, with more than 2200 articles listed in PubMed. Nevertheless, the brain substrates of ADHD remain poorly understood. This reflects the crisis of replicability across nearly all scientific endeavors, deriving from factors such as small sample sizes combined with a proliferation in analytical approaches, yielding high rates of false positive results. The field of molecular genetics confronted this by adopting open and immediate sharing of raw data and insistence on rigorous corrections for multiple comparisons. These strategies are yielding more robust genetic findings, albeit with much smaller effect sizes than before. This brief review focuses on two recent consortium efforts, i.e., the international Enhancing Neuro-Imaging Genetics through Meta-Analysis (ENIGMA), and the U.S. Adolescent Behavior & Cognitive Developm ent Study (ABCD). Both embrace the culture of open science, and are beginning to yield credible findings, despite being limited initially to cross-sectional analyses. As the field continues to mature, these and other ongoing longitudinal large-scale studies are poised to transform our understanding of the pathophysiology of ADHD to bring closer the day when neuroimaging can contribute to clinical utility.