Clinical Outcomes of Extended-Release Guanfacine in Adults With Attention-Deficit/Hyperactivity Disorder: A...

Introduction Adult attention-deficit/hyperactivity disorder (ADHD) is a clinically important neurodevelopmental condition with a substantial global prevalence. Extended-release guanfacine (GXR) is a non-stimulant selective α2A-adrenergic receptor agonist approved for adult ADHD in Japan, but real-world adult data remain limited. Materials and methods We conducted a retrospective medical chart review of consecutive eligible adults with ADHD treated with GXR at an ADHD specialty clinic in Japan. ADHD was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria by experienced psychiatrists. Clinical Global Impression-Severity (CGI-S), GXR dose, treatment continuation at week 10, Clinical Global Impression-Improvement (CGI-I), and treatment-emergent adverse events (TEAEs) were extracted from medical records. Continuous variables were summarized as mean±standard deviation (SD) and categorical variables as number and percentage. Exact binomial 95% confidence intervals (CIs) were calculated for proportions. Exploratory baseline comparisons by treatment continuation status were performed using the Shapiro-Wilk test, Welch t-test, or Mann-Whitney U test for continuous variables and the Fisher exact test for categorical variables. Statistical analyses were performed using EZR, a graphical user interface for R. Results Among 137 participants, 111 (81%; 95% CI: 73.4-87.2%) continued GXR treatment for 10 weeks. Among the 111 participants with week-10 CGI-I data, 58 (52.3%; 95% CI: 42.6-61.8%) were rated as very much improved or much improved. TEAEs were recorded in 76 participants (55.5%; 95% CI: 46.7-64%), and no serious TEAEs were observed. Conclusions These findings suggest that GXR may be a clinically useful and generally well-tolerated treatment option for adults with ADHD in routine practice in Japan. The results support cautious real-world titration and highlight the need for prospective studies using standardized adult ADHD outcome measures.