Iwanami A, et al. - This study was sought to investigate guanfacine extended-release (GXR) efficacy and safety in adults with attention-deficit/hyperactivity disorder (ADHD). Researchers designed a phase 3, double-blind, placebo-controlled study (conducted between October 2016 and July 2017) including Japanese patients aged ≥ 18 years with ADHD (DSM-5). Primary outcome included alteration from baseline in total score on the Japanese version of the ADHD-Rating Scale IV with adult prompts (ADHD-RS-IV) at week 10. The ADHD-RS-IV subscales, Clinical Global Impression–Improvement scale (CGI-I) and Patient Global Impression–Improvement scale (PGI-I) (percentage of patients very much improved/much improved), treatment-emergent adverse event (TEAE) incidences, and TEAEs leading to discontinuation were considered as other measures. The ADHD symptoms were improved by GXR without any major safety concerns in Japanese adults with ADHD.