Co-occurring attention-deficit/hyperactivity disorder and anxiety disorders differentially affect males and females with autism.

Objective To examine overlap and divergence of symptomatology in Autism Spectrum Disorder (ASD) with and without co-occurring Attention/Deficit Hyperactivity Disorder (ADHD) and/or Anxiety Disorder by age and sex. Method Participants included 25,078 individuals registered in the SPARK cohort, age 6-18 years. SPARK participation includes online consent and registration, as well as parent-reported ASD, ADHD, and Anxiety Disorder diagnoses, developmental, medical, and intervention history, and standardized rating scales. Individuals with ASD, ASD + ADHD, ASD + Anxiety, or ASD + ADHD + Anxiety were compared on measures assessing social communication, restricted and repetitive behaviors (RRBs), and motor functioning, and differences between male and female profiles were examined. Results Significant differences in symptom presentation between females/males, school-age/adolescent individuals, and by co-occurring conditions (ASD/ADHD/Anxiety) are apparent, and the impact of co-occurring conditions differed by age and sex. Most notably, school-age femaleswith ASD without co-occurring conditions present with significantly fewer concerns about social communication skills and have better motor skills, but have more prominent RRBs as compared to same-aged males with ASD alone; co-occurring conditions were associated with increased social communication problems and motor concerns, most consistently for school-age females. Conclusions School-age females with ASD are at highest risk for underestimation of autism-related symptoms, including underestimation of symptoms beyond core ASD features (motor skills). Further, across ages, particular consideration should be given when probing for social communication symptoms, RRBs, and motor skills in females with ASD alone, as well as with co-occurring ADHD and/or Anxiety. For females with co-occurring symptoms and conditions, use of symptom-specific measures in lieu of omnibus measures should be considered.