Melatonin rhythm disorder is more pronounced in major depressive disorder with Non-Suicidal Self-injury

Abstract Background Melatonin(MT) rhythm disorders may be associated with depression and non-suicidal self-injury（NSSI）.We conducted a controlled study to investigate whether patients with major depressive disorder（MDD）comorbid NSSI have more pronounced MT disorders, and whether MT levels are associated with NSSI perception and cessation. Methods A total of 100 samples were included in the study, including 30 healthy individuals as a normal control group and 70 patients with MDD.In the subgroup of MDD,there were 35 patients with NSSI(NSSI group) and 35 patients without NSSI (non-NSSI group).We used enzyme-linked immunosorbent assay to measure the salivary MT levels (0AM, 8AM, 11AM, 1PM, 4PM, 10PM) of all participants at 6 time points. And use the Ottawa-Self- Injury Inventory (OSI) to quantitatively evaluate the self injury perception and motivation to stop self injury in patients in the NSSI group. Results The salivary MT levels in the NSSI group at 6 time points were significantly lower than those in the non- NSSI group and control group (P<0.05), and the circadian rhythm of MT in NSSI group disappeared.We found significant correlations between MT levels and several dimensions of NSSI,specifically: 1PM MT level and intrusive/invasive urge(r=0.487，P<0.05), 8AM MT levels and desire to stop NSSI(r=-0.427，P<0.05),11AM MT levels and desire to stop NSSI(r=-0.348，P<0.05). Conclusions The decrease in MT levels and disruption of circadian rhythms may increase the risk of NSSI in patients with MDD, but its mechanism needs further exploration.