Results of a Mendelian randomization study, published in the Journal of Attention Disorders, did not support a causal relationship between circulating unsaturated fatty acid (UFA) levels and attention-deficit/hyperactivity disorder (ADHD). Although previous evidence has demonstrated that UFAs are essential nutrients for neurodevelopment, brain function, and mental health, it remains unclear as to whether the concentration and functionality of circulating UFAs exert a causal effect on ADHD risk.