What role does COMT play in sleep?

COMT (catechol-O-methyltransferase) is an enzyme that breaks down dopamine and norepinephrine. The common rs4680 (Val158Met) variant alters enzyme activity: the Met allele reduces activity, leading to higher prefrontal dopamine levels. Studies suggest this variant may influence sleep architecture – potentially increasing REM sleep but also contributing to greater sleep fragmentation and higher insomnia vulnerability under stress. There is also evidence linking COMT to circadian preference (morningness/eveningness) and response to sleep deprivation. However, effect sizes are small, context-dependent, and modulated by other genes, environment, and lifestyle. No direct clinical recommendations can be derived from a COMT genetic test alone. The evidence is based on moderate human studies, not large randomized trials. A genetic test cannot reliably predict individual sleep quality. For sleep issues, focus on sleep hygiene and consult a physician if problems persist.