Sally is now 25-years-old and has noticed how much her inattention is creating problems at her job. At home, she easily loses things, can’t get organized and is highly distractible. Her friend, who has been diagnosed with ADHD since childhood, told her to be evaluated. “You have a lot of the same issues I do. Maybe you have ADHD.” But Sally was never diagnosed with ADHD as a child. Is it possible she could develop ADHD as an adult?

Some adults who are diagnosed with ADHD as adults do not report childhood histories consistent with ADHD. Even though ADHD is seen as a neurodevelopment childhood disorder that continues into adulthood, three recent studies point to possible adult onset for ADHD.

Study 1 (See below): This study followed 1037 children born in New Zealand to the age of 38. All met criteria for diagnosis of ADHD.  Data was obtained from multiple sources like teachers, parents, testing, etc. The study concluded that those adults studied may not have had childhood onset. The authors raise the question, could adult onset have similar characteristics as childhood ADHD but be a different disorder?

Study 2 (See below): This study followed 5249 people raised in the same town in Brazil from birth to ages 18-19. At age 11, 9% of the children in the study met criteria for the DSM-5 diagnosis of ADHD. They too found that adult onset looked different than childhood and wondered if these are two different syndromes.

Study 3 (See below): The researchers studied a large sample of same gendered twins. They concluded that there is a difference between late and early onset of ADHD but the symptoms look similar.

One question for all three studies is, because childhood symptoms were not reported, does that mean they were not present. Overall, researchers are looking at how people with ADHD diagnosed in childhood may differ from those with adult onset. These studies support the idea that adult onset is possible.

References: 

Study 1: Moffitt et al. Is Adult ADHD a Childhood-Onset Neurodevelopmental Disorder? Evidence From a Four-Decade Longitudinal Cohort Study. Am J Psychiatry. 2015 Oct;172(10):967-77. PubMed PMID: 25998281; PubMed Central PMCID: PMC4591104.

Study 2: Caye et al. Attention-Deficit/Hyperactivity Disorder Trajectories From Childhood to Young Adulthood: Evidence From a Birth Cohort Supporting a Late-Onset Syndrome. JAMA Psychiatry. 2016 Jul 1;73(7):705-12. PubMed PMID: 27192050.

Study 3: Agnew-Blais et al. Evaluation of the Persistence, Remission, and Emergence of Attention-Deficit/Hyperactivity Disorder in Young Adulthood. JAMA Psychiatry. 2016 Jul 1;73(7):713-20. PubMed PMID: 27192174.