What to watch with COMT and sleep?

COMT (catechol-O-methyltransferase) degrades dopamine. The Val158Met variant (rs4680) affects enzyme activity: Met/Met (slow) → higher dopamine, often better sleep quality but more caffeine sensitivity; Val/Val (fast) → lower dopamine, potentially lighter sleep but more evening alertness. Studies suggest Met carriers experience greater sleep disruption from afternoon/evening caffeine. Practical advice: limit caffeine to morning hours, especially if Met/Met. However, COMT is just one piece of the sleep puzzle (circadian genes, melatonin, stress). Consumer DNA tests provide insight, not diagnosis. Evidence: human-moderate (multiple association studies, no clinical guideline).