Relationship Between Intellectual Disability and Behavioral Comorbidity in Children With Fragile X Syndrome.

The analyses were cross-sectional and used baseline data, so they cannot show that intellectual disability caused a behavioral condition or that behavior changed over time. With the exception of current autism spectrum disorder, the paper did not report specific standardized guidelines for assessing the other comorbidities. Ever autism spectrum disorder diagnosis was based on caregiver recollection and often lacked documentation. The sensory problems scale was ad hoc and not formally validated. The Social Responsiveness Scale and Social Communication Questionnaire may also reflect other social problems, such as social anxiety, not only autism spectrum disorder. Subtype proportions and profiles differed from a previous analysis because of a revised dataset and handling of missing data, so subtype-specific numbers should be read cautiously. Children with developmental delay were not included in inferential analyses, and they could later develop intellectual disability of different severity. The whole-sample analyses used all 1,400 participants, but subtype analyses used only 1,055 males and 326 females with complete datasets. The association between obsessive/perseverative behavior and the Aberrant Behavior Checklist Stereotypy subscale was weak, so the intellectual disability link for that condition needs caution.

WEK is a consultant for Anavex Life Sciences, Shionogi, Quince Therapeutics, Acadia Pharmaceuticals, and Taysha Gene Therapies. DBB has been principal investigator on clinical trials funded by Ovid Therapeutics and Zynerba Pharmaceuticals and has consulted for Ovid Therapeutics. HKH is a co-investigator on clinical trials funded by Ionis Pharmaceuticals, Neuren Pharmaceuticals and Clinical Research Associates, LLC. The other co-author declares no competing interests.

Do not conclude that intellectual disability causes these behavioral comorbidities or that higher intellectual disability means every behavioral problem will be worse. The study is cross-sectional and used baseline clinician-reported diagnoses, and anxiety and attention or hyperactivity symptoms were not associated with intellectual disability level.