The relationship between substance craving and melatonin levels in patients with methamphetamine use disorder.

OBJECTIVES

The aim of this study was to determine plasma melatonin levels in individuals with methamphetamine use disorder (MUD) and to evaluate the relationship with substance craving.

METHODS

The study included 30 male patients with MUD receiving inpatient treatment at the Alcohol and Drug Addiction Treatment and Research Center and 20 healthy male controls. Venous blood samples were collected at 23:00, 02:00 and 06:00 and plasma melatonin levels were measured by ELISA. The Insomnia Severity Index (ISI) and Substance craving scale (SCS) were administered.

RESULTS

Melatonin levels at 23:00, 02:00, and 06:00 were significantly lower in the MUD group (p < 0.001). In the MUD group, melatonin levels rose across the night and peaked at 06:00. Melatonin levels of all blood samples showed a significant negative correlation with SCS scores.

CONCLUSIONS

These findings indicate that melatonin levels are reduced in MUD patients and this may be related to substance craving. Melatonin may serve as a biomarker in circadian irregularity associated with addiction.