Attention-deficit/hyperactivity disorder (ADHD) is a common and complex neurodevelopmental disorder that affects individuals across the lifespan. This review provides an overview of the DSM diagnostic criteria for ADHD and discusses recommended considerations for the diagnosis of ADHD in children, adolescents, and adults. Its complexity requires careful consideration in the diagnostic process due to heterogeneity in clinical presentation and symptom overlap with other conditions. Commonly used…