By what age must symptoms of ADHD be present for a diagnosis?

For a diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD), symptoms must typically manifest before the age of 12. This criterion is part of the diagnostic guidelines established by the American Psychiatric Association in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). It is essential for the symptoms to be present during this developmental period, as identifying behaviors consistent with ADHD in early childhood or early school years can help differentiate them from typical variations in child behavior.

Symptoms that arise after the age of 12 may not conform to the established diagnostic criteria, as the disorder is often characterized by a longstanding pattern of inattention and/or hyperactivity-impulsivity that can be traced back to childhood. Therefore, the age cut-off of 12 years ensures that the diagnosis reflects an ongoing and persistent condition rather than behaviors that may be situational or developmental in nature. This age threshold is vital for clinicians to make an accurate diagnosis and develop appropriate treatment plans for managing ADHD.