Investigating late‐onset ADHD: a population cohort investigation

Abstract

BackgroundAdult ADHD has been assumed to be a continuation of childhood‐onset ADHD. However, recent studies have identified individuals with ADHD in adulthood who have not had ADHD in childhood. Whether or not these individuals have a ‘typical’ neurodevelopmental profile is not clear.MethodsWe tested two explanations for the emergence of apparent late‐onset ADHD symptomatology using the ALSPAC epidemiological cohort, by grouping individuals according to their scores on the Strengths and Difficulties Questionnaire (SDQ) hyperactivity subscale at ages 12 and 17 years. First, we tested whether some of those with apparent late‐onset ADHD symptoms had been potentially misclassified on the basis of earlier SDQ hyperactivity scores (ages 7, 8 and 9 years) or of subthreshold symptoms at age 12 years. Second, we investigated the possibility that those with ‘genuine’ late‐onset ADHD symptoms had a delayed manifestation of the same liability that underlies childhood‐onset symptoms, by investigating whether they had a similar profile of neurodevelopmental impairments (in the domains of autistic symptomatology, language, reading, spelling, executive functioning and IQ) as those with typical childhood‐onset ADHD.Results N = 56/75 (75%) of those with apparent late‐onset ADHD had had high ADHD scores at least one point in childhood, suggesting that they may have been misclassified on the basis of their score at age 12 years. The remaining 19 individuals (25%) with genuine late‐onset ADHD symptoms did not show a profile of neurodevelopmental impairment typically seen in ADHD, instead showing similar levels of autistic symptoms, language skills, executive functioning ability and IQ to those without ADHD symptoms. The only exceptions were that this group showed reading and spelling problems at age 9 years.ConclusionsOur work suggests that this small number of individuals with genuine late‐onset symptoms may not be most appropriately considered as having a typical neurodevelopmental disorder.

Heterotypic trajectories of dimensional psychopathology across the lifespan: the case of youth‐onset attention deficit/hyperactivity disorder

“…In 2015, Moffit and collaborators published a pioneering study demonstrating that nearly 90% of adult ADHD cases in the Dunedin cohort were de novo cases (Moffitt et al., ). Investigators replicated the findings on the existence of late‐onset ADHD in three other large cohort samples: E‐Risk (Agnew‐Blais et al., ), Pelotas Birth Cohort (Caye et al., ) and ALSPAC (Cooper et al., ; Riglin et al., ). These findings raised a debate on whether adult ADHD could be considered a childhood‐onset neurodevelopmental disorder, questioning whether late‐onset ADHD might represent a distinct disorder from childhood‐onset ADHD (Castellanos, ; Moffitt et al., ).…”

“…The first ALSPAC study (Riglin et al., ), which assesses adolescents, did not primarily aim to investigate a specific adolescent‐onset trajectory of ADHD. However, more recently, the ALSPAC data were re‐analyzed in order to specifically investigate an ADHD onset in adolescence (Cooper et al., ). This study showed that there is a distinct group of adolescent‐onset cases, despite the fact that a large proportion of these potential youth‐onset cases were actually misclassified on the basis of their earlier hyperactivity scores on the Strengths and Difficulties Questionnaire (SDQ).…”

“…Therefore, the question of whether late‐onset ADHD can, in fact, be a phenomenon occurring predominantly during adolescence (and not adulthood) still needs further investigation. Second, the recent study for the ALSPAC cohort (Cooper et al., ) indicates the importance of specific strategies to exclude subthreshold ADHD cases in childhood, something that has not been addressed in other population‐based studies. Since DSM‐5 ADHD criteria state that several of the ADHD symptoms have to start before the age of 12, to assure the validity of a late‐onset ADHD conception, the inclusion in this group should be based on asymptomatic children or children with very few symptoms in childhood, an analysis still to be performed in population studies.…”

The Positive Aspects of Attention-Deficit/Hyperactivity Disorder among Famous People

“…Interest in adult ADHD has recently increased, 1 and cases of late-onset ADHD in adulthood in individuals without a history of childhood ADHD have recently been reported. 2 Furthermore, there has been recent controversy surrounding the diagnosis of ADHD in children and adults. 3 The primary symptoms of ADHD differ according to ADHD subtypes, and its progress varies, which have resulted in disagreements over the diagnosis of ADHD.…”

Development of the Korean Practice Parameter for Adult Attention-Deficit/Hyperactivity Disorder

“…Moffitt et al [64] and Agnew-Blais et al [65] observed the Dunedin birth cohort and England and Wales twin birth cohorts, respectively, and reported late-onset ADHD without any childhood history. Cooper et al [66] also reported adult onset ADHD with normal childhood development from a UK birth cohort, which ignited the possibility of a previously unidentified form of ADHD that arises entirely during adulthood. However, there are some caveats to these studies, such as the possibility of biased retrospective recall by the parents for the four-decadelong longitudinal cohort study conducted in Dunedin, New Zealand [64].…”