In the past decade, there have been substantial changes in diagnostic nomenclature. This study investigated sex differences in attention-deficit/hyperactivity disorder (ADHD) symptom severity based on Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV, DSM-IV(TR), and DSM-5 criteria, separating rating scale and clinical interview data in children and adults with ADHD. PubMed, PsycINFO, and Scopus were searched for published studies (1996-2021) reporting severity of attention, and…