Circadian melatonin profile in opium and amphetamine dependent patients: A preliminary study.

Aim: The aim of this study was to investigate the relationship between opium and amphetamine dependency with the serum melatonin levels in the presence of circadian rhythm sleep disorders (CRSD).

Participants: Forty four male amphetamine-dependent and opium-dependent patients with CRSD and with more than one year substance dependency were enrolled in this study. Control group consisted of twelve healthy male subjects.

Design: The diagnoses of sleep disorders were established by a psychiatrist and were made on the basis of the criteria of ICSD-II using the patients' sleep logs. Blood samples were drawn every 4 h through an intravenous catheter. Serum melatonin levels were assayed using an enzyme-linked immunosorbent assay (ELISA) kit. Repeated Measures Analysis of variance (ANOVA) was used to assess differences between the melatonin levels at six separate times.

Finding: The serum melatonin levels of the control subjects were significantly higher than both opium-dependent and amphetamine-dependent patients at 24:00, 4:00 and 8:00. The serum melatonin level of the opium-dependent patients were significantly lower than the amphetamine-dependent patients at 24:00 (26.9 ± 11.4 vs. 41 ± 19.4, respectively; p = 0.006) and were significantly higher than the amphetamine-dependent patients at 16:00 (12.7 ± 5.1 vs. 8.9 ± 4.1, respectively; p = 0.011).

Conclusion: This is an evidence of negative effects of substance dependence on circadian cycle of melatonin secretion among opium and amphetamine dependent patients.