Adult attention deficit hyperactivity disorder

Adult Attention Deficit Hyperactivity Disorder (adult ADHD) refers to ADHD that persists into adulthood. It is a neurodevelopmental disorder, meaning impairing symptoms must have been present in childhood, except for when ADHD occurs after traumatic brain injury. According to the DSM-5 diagnostic criteria, multiple symptoms should have been present before the age of 12. This represents a change from the DSM-IV, which required symptom onset before the age of 7. This was implemented to add flexibility in the diagnosis of adults. ADHD was previously thought to be a childhood disorder that improved with age, but later research challenged this theory. Approximately two-thirds of children with ADHD continue to experience impairing symptoms into adulthood, with symptoms ranging from minor inconveniences to impairments in daily functioning, and up to one-third continue to meet the full diagnostic criteria.

This new insight on ADHD is further reflected in the DSM-5, which lists ADHD as a “lifespan neurodevelopmental condition,” and has distinct requirements for children and adults. Per DSM-5 criteria, children must display “six or more symptoms in either the inattentive or hyperactive-impulsive domain, or both,” for the diagnosis of ADHD. Older adolescents and adults (age 17 and older) need to demonstrate at least five symptoms before the age of 12 in either domain to meet diagnostic criteria. The International Classification of Diseases 11th Revision (ICD-11) also updated its diagnostic criteria to better align with the new DSM-5 criteria, but in a change from the DSM-5 and the ICD-10, while it lists the key characteristics of ADHD, the ICD-11 does not specify an age of onset, the required number of symptoms that should be exhibited, or duration of symptoms. The research on this topic continues to develop, with some of the most recent studies indicating that ADHD does not necessarily begin in childhood.

A final update to the DSM-5 from the DSM-IV is a revision in the way it classifies ADHD by symptoms, exchanging "subtypes" for "presentations" to better represent the fluidity of ADHD features displayed by individuals as they age.