Evidence check: COMT in the context of sleep

COMT (catechol-O-methyltransferase) regulates dopamine breakdown. The well-studied rs4680 (Val158Met) variant alters enzyme activity: Met carriers have lower activity, leading to higher prefrontal dopamine. Some studies link this variant to sleep quality, sleep onset, and circadian preference, but findings are mixed. Met carriers may have slightly better sleep efficiency, while Val/Val individuals might be more vulnerable to stress-induced sleep disruption. However, effect sizes are small, and many confounders (age, sex, lifestyle, other genes) play a role. COMT is often analyzed in polygenic contexts (e.g., with CLOCK, PER3). A standalone COMT test from a consumer DNA kit cannot diagnose sleep disorders or guide treatment. Evidence is human-moderate: observational and candidate-gene studies, not clinical trials. For sleep issues, focus on sleep hygiene, stress management, and medical evaluation rather than genetic testing.