Although its mechanism differs from existing ADHD treatments, the FDA classifies SIMTRIYO as a central nervous system (CNS) stimulant. Otsuka reported that the studies found statistically significant improvements in ADHD symptoms compared with placebo. How SIMTRIYO Takes a Different Route Through the BrainSIMTRIYO works by inhibiting the reuptake of norepinephrine, dopamine and serotonin. Another Option for People Still Searching for Effective TreatmentFinding an effective ADHD treatment can require an individualized approach. The Phase 3 program included studies in adults and children and found improvements in ADHD symptoms compared with placebo.