Abstract
Autism Spectrum Disorder (ASD) often co-occurs with Attention-Deficit/Hyperactivity Disorder (ADHD), exacerbating functional challenges. Standard ADHD treatments are often less effective and less well tolerated in ASD. Guanfacine XR, a non-stimulant ADHD medication, shows promise for managing hyperactivity and irritability in ASD-ADHD but with mixed results. This retrospective study analyzed data from 29 children aged 6–18 years with ASD-ADHD treated with Guanfacine XR at three healthcare centers. Clinicians initiated Guanfacine XR in cases with persistent ADHD symptoms, partial response, or side effects associated with psychostimulants or atomoxetine. Guanfacine was administered as monotherapy in some cases and as adjunctive therapy to psychostimulants or atomoxetine in others, depending on previous ADHD treatment response. Pre- and post-treatment scores from the Aberrant Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Conners Parent and Teacher Rating Scales (CPRS-RS, CTRS-RS) were compared. Adverse effects and vital sign changes were documented. Of 29 participants completing treatment, significant reductions were seen in hyperactivity, irritability, and stereotypy scores. Improvements in irritability mediated reductions in hyperactivity and stereotypy. However, three children discontinued treatment due to increased irritability. Common side effects included somnolence, increased appetite, and dizziness, while vital sign changes were minimal and tolerable. Guanfacine XR may effectively reduce hyperactivity and irritability in ASD-ADHD, with hyperactivity improvements mediated via reduced irritability and stereotypy. However, individual variability, including cases of increased irritability, warrants careful monitoring. Its tolerability supports its use in polypharmacy, though further research is essential.