Disentangling autism spectrum and attention-deficit/hyperactivity symptoms over development in fragile X syndrome.
In fragile X, early ADHD signs forecast later autism traits, so treating ADHD may prevent some social-communication problems.
01Research in Context
What this study did
Luckasson et al. (2020) followed boys with fragile X syndrome for three years. Each year they scored ADHD and autism symptoms.
They asked: do early ADHD signs predict later autism signs, even after accounting for age and IQ?
What they found
ADHD symptoms at the first visit predicted more autism symptoms one and two years later.
The link stayed strong after removing the effects of age and IQ.
How this fits with other research
The same directional link shows up outside fragile X. McGonigle et al. (2014) saw that preschoolers with high ADHD symptoms later showed more autism and internalizing problems.
Klusek et al. (2022) extended the window, finding that 42 % of older FXS males still meet ADHD criteria.
Ohan et al. (2015) looked at the other end of life: among adult FXS men, autism diagnosis rates stay flat with age. Ruth’s data now fill the gap in between, showing the ADHD-to-autism pathway starts early and persists.
Why it matters
If you serve boys with fragile X, treat ADHD behaviors now. Reducing impulsivity and inattention may soften later social-communication struggles. Add an ADHD screener to your intake battery and revisit it yearly.
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02At a glance
03Original abstract
Even genetic disorders associated with monogenic aetiologies are characterized by complex and variable risk for poor outcomes, highlighting the need to follow trajectories longitudinally. Here, we investigated the longitudinal relationships between attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) symptoms in a population at high risk for both: boys with fragile X syndrome. 59 boys with fragile X syndrome aged 3-10 years old at entry participated in this study, and were followed up one and two years after their first visit. As expected, we found strong relationships over three timepoints for ADHD symptoms (as measured by the parent-rated Conners scale) and ASD symptoms (as measured by the Social Communication Questionnaire [SCQ]). In addition, using structural equation modeling (SEM) we found that ADHD symptoms at time 2 predicted ASD symptoms at time 3, suggestive of a causal relationship. Importantly, these relationships hold when including chronological age at entry to the study, as well as when including severity of impairment as measured by IQ, and their effects on both ASD and ADHD symptoms do not reach significance. This result highlights the need to study outcomes longitudinally and it informs the comorbidity of the two symptom domains in FXS as well as their potential directionality, both of which have been little researched. In addition, our findings may suggest a future need to study how ADHD symptoms and their treatment impact individuals with ASD.
Research in developmental disabilities, 2020 · doi:10.1016/j.ridd.2020.103692