LAUSR

This investigation was designed to determine the effect of melatonin supplementation on mental health parameters, metabolic and genetic profiles in patients under methadone maintenance treatment (MMT). This randomized, double‐blind, placebo‐controlled, clinical trial was conducted among 54 patients under MMT. Participants were randomly allocated to receive either 10 mg melatonin (2 melatonin capsules, 5 mg each) (n = 26) or placebo (n = 28) once a day, 1 hour before bedtime for 12 weeks. Melatonin supplementation significantly decreased Pittsburgh Sleep Quality Index (β −4.08; 95 percent CI, −5.51, −2.65; P < 0.001), Beck Depression Inventory index (β −5.46; 95% CI, −8.92, −2.00; P = 0.003) and Beck Anxiety Inventory index (β −3.87; 95% CI, −5.96, −1.77; P = 0.001) and significantly increased International Index of Erectile Functions (β 5.59; 95% CI, 1.76, 9.42; P = 0.005) compared with the placebo. Subjects who received melatonin supplements had significantly lower serum insulin levels (β −2.53; 95% CI, −4.48, −0.59; P = 0.01), homeostasis model of assessment‐insulin resistance (β −0.56; 95% CI, −1.03, −0.09; P = 0.01) and higher quantitative insulin sensitivity check index (β 0.01; 95% CI, 0.004, 0.02; P = 0.009) and HDL‐cholesterol levels (β 3.71; 95% CI, 1.77, 5.64; P = 0.002) compared to placebo. Additionally, melatonin intake resulted in a significant reduction in serum high sensitivity C‐reactive protein (β −0.15; 95% CI, −0.27, −0.02; P = 0.02), malondialdehyde (β −0.31; 95% CI, −0.57, −0.05; P = 0.02) and protein carbonyl (β −0.06; 95% CI, −0.09, −0.04; P < 0.001). This trial indicated that taking melatonin supplements for 12 weeks by patients under MMT had beneficial effects on their mental health metabolic profiles.