By what age must symptoms of ADHD manifest for a formal diagnosis?

For a formal diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD), it is required that symptoms must be present by a certain age, as outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Symptoms typically need to manifest before the age of 12. This criterion is in place to ensure that the diagnosis reflects a long-standing pattern of behavior that has been observed in the individual's developmental history.

Detecting symptoms early provides essential insights into a child's behavior and helps in distinguishing ADHD from other issues that might arise later in life. By requiring symptoms to appear before this age, clinicians can better assess the disorder's impact on functioning over time, ensuring that it is not merely a phase that will resolve on its own as the child matures.