An 18-year follow-up study published in Psychiatry Research provides evidence that children diagnosed with attention-deficit/hyperactivity disorder tend to face broader challenges in adulthood across multiple areas of life compared to their peers. The study evaluated adults who were diagnosed in childhood alongside their non-ADHD siblings and an unrelated control group. The findings indicate that siblings of children with ADHD generally experience typical adult functioning, suggesting that many long-term difficulties are specific to the condition itself rather than shared family upbringing.
Attention-deficit/hyperactivity disorder, commonly known as ADHD, is a neurodevelopmental condition marked by ongoing patterns of inattention, hyperactivity, and impulsivity. It affects roughly 5% to 7% of children worldwide. Although it was once considered a condition that individuals would outgrow, scientists now recognize that symptoms often persist into adulthood.
Longitudinal studies track the same individuals over extended periods, allowing scientists to observe how childhood health conditions unfold over time. Past research suggests that adults who were diagnosed with ADHD as children may experience higher rates of mood disorders, lower educational attainment, and reduced job stability. However, many existing studies have focused primarily on clinical symptoms rather than examining broad daily functioning, such as physical health, sleep quality, and social relationships.
“As part of my doctoral research I had the opportunity to follow-up a longitudinal cohort of children with ADHD, their siblings, and controls,” explained lead author Noa van der Plas, a doctoral researcher at Vrije Universiteit Amsterdam. “This cohort had been followed throughout childhood, but their most recent comprehensive follow-up had taken place 10 years ago.”
“Now that they had reached adulthood, we wanted to know how these children had grown up,” van der Plas told PsyPost. “While ADHD is known to be related to difficulties and impairment in childhood, much less is known about the long-term development of ADHD. Our aim was to investigate a broad range of aspects of daily functioning in adulthood among individuals who had been diagnosed with ADHD in childhood.”
To better understand the origins of adult difficulties, researchers examine the biological family members of individuals with ADHD. Full siblings share approximately 50% of their inherited genetic material and typically grow up in similar home environments with the same parents. Evaluating siblings alongside individuals with ADHD allows researchers to separate genetic and environmental influences from risks directly linked to the diagnosis itself.
The authors evaluated data from an 18-year prospective study originating from a cohort in the Netherlands. The sample included 154 adults diagnosed with childhood ADHD (averaging 28.7 years of age, 68% male), 138 siblings without childhood ADHD (averaging 29.6 years of age, 35% male), and 129 controls without a family history of ADHD (averaging 28.2 years of age, 40% male). On average, researchers re-evaluated participants 17.6 years after their initial inclusion in the study during childhood.
To gather comprehensive data, participants completed self-reported online surveys and standardized clinical interviews over secure video calls. Participants also designated a close friend, partner, or parent to complete observer questionnaires to provide outside perspectives on daily behaviors. The evaluation assessed seven key areas of adult life: psychiatric status, behavioral and emotional problems, academic and professional history, daily adaptive functioning, neurocognitive performance, physical health, and healthcare usage.
Statistical analyses revealed that adults diagnosed with childhood ADHD performed worse than control participants on over 60% of the measured outcomes. In terms of psychiatric status, 45% of participants in the childhood ADHD group met full diagnostic criteria for adult ADHD at follow-up. Major depressive disorder was diagnosed in 18% of adults with childhood ADHD, compared to 8% of controls and 6% of siblings.
“Children with ADHD are at an increased risk of challenges in adult functioning, including difficulties related to mental health, social functioning, and daily functioning,” van der Plas noted. “Notably, the risk of having a major depressive disorder in adulthood was greater for adults with childhood ADHD.”
Behavioral assessments showed that adults who had childhood ADHD reported higher levels of externalizing problems, which involve outward-directed difficulties like impulsive or aggressive actions. They also reported higher levels of autistic traits, mood dysregulation, physical aggression, and social aggression compared to control participants. In educational domains, individuals with childhood ADHD attained lower average levels of formal education and performed lower on neurocognitive measures of working memory and verbal fluency.
In measures of adaptive functioning and physical health, adults with childhood ADHD reported higher perceived stress and lower emotional well-being. They also demonstrated higher average body mass index values, worse sleep quality, and lower adherence to dietary guidelines established by national nutrition centers. Additionally, adults in the childhood ADHD group were significantly more likely to be currently prescribed ADHD medication compared to both siblings and control participants.
The sibling group demonstrated adult functioning that was largely comparable to the control group across most measures. “In childhood the siblings of the children with ADHD are at an increased risk of ADHD-related traits and show an intermediate neurocognitive profile compared to controls,” van der Plas explained. “Based on those findings we expected siblings to also show more difficulties in adult functioning. However, we found few differences between siblings and controls in adulthood.”
Siblings showed slightly elevated levels of self-reported ADHD traits and autistic traits, as well as slightly higher body mass index values compared to controls, but lacked major psychiatric or academic setbacks. “Finally, although the siblings of children with ADHD share half of their genetic material as well as part of their childhood environment, these siblings generally did not have an increased risk of problems in adulthood,” van der Plas said.
When comparing individuals whose ADHD persisted into adulthood against those whose condition remitted, specific patterns emerged. The persistent ADHD group displayed the highest risks for major depressive disorder, internalizing problems, severe stress, and poor sleep quality. However, adults whose childhood ADHD had remitted still showed lower educational attainment and lower cognitive scores compared to control participants, suggesting long-lasting impacts on learning.
The researchers emphasized that despite overall group differences, there is substantial diversity in how adults with childhood ADHD fare. “However, there is variability in the functioning of adults with childhood ADHD, and the majority of adults with childhood ADHD show functioning comparable to controls,” van der Plas told PsyPost. “There seems to be a subset of adults with childhood ADHD particularly experiencing impairment, which seems to be partly linked to a continued ADHD diagnosis.”
The author highlighted a key misinterpretation that she hopes the public will avoid when viewing the research. “Although, on average, adults with a childhood diagnosis of ADHD are more likely to experience difficulties in functioning, most are functioning comparably to individuals without ADHD,” van der Plas added.
Several limitations should be considered when evaluating these findings. The study sample was composed exclusively of individuals of Caucasian descent living in the Netherlands, which limits how well the conclusions apply to more diverse racial or cultural populations. Selective participant drop-out occurred over the 18-year period, as only a portion of the original childhood cohort was successfully re-evaluated.
The retained childhood ADHD group had slightly higher childhood symptom severity than those who dropped out, meaning the results may reflect outcomes for individuals with somewhat more severe early symptoms. Additionally, cognitive testing was conducted remotely over video calls rather than in a standardized physical laboratory, which might introduce minor variations in home testing environments.
“In other work of my doctoral research we additionally looked at specific medication outcomes, sex and gender differences in the long-term outcomes of childhood ADHD, the long-term outcomes of stimulant treatment in childhood, and attempted to identify predictors for long-term outcomes,” van der Plas said regarding her broader research goals. “Future research should investigate the risk and protective factors that are related to the differences in functioning in adults with childhood ADHD and identify which individuals are most at risk,” van der Plas concluded. “This knowledge can help improve prevention or intervention strategies.”
The study, “Growing up with ADHD: findings from an 18-year longitudinal follow-up study of adults with childhood ADHD, their siblings, and controls,” was authored by Noa E. van der Plas, Siri D.S. Noordermeer, Barbara Franke, Catharina A. Hartman, Pieter J. Hoekstra, Nanda N.J. Rommelse, Emma Sprooten, Marjolein Luman, and Jaap Oosterlaan.