Correlation of Circadian Rhythms and Improvement of Depressive Symptoms in Acute Ischemic Stroke Patients

Objectives: To investigate the correlation between evening melatonin timing secretion, dim light melatonin onset (DLMO), and post-stroke depression (PSD) in acute ischemic stroke patients and their influence on the improvement of depressive symptoms. Materials and Methods: 120 patients with a recent magnetic resonance imaging confirmed stroke were included. Salivary melatonin samples were collected at 5 time points within 1 week after hospitalization (7 p.m.-11 p.m., 1 sample per hour). The circadian phase was defined by calculating DLMO secretion. Post-stroke depressive symptoms were evaluated by the 17-item Hamilton Rating Scale for Depression (HRSD) both on day 7 of hospitalization and 3 months after stroke. Patients were divided into PSD and non-PSD groups based on whether the acute phase HRSD score was ≥8. Similarly, patients were divided into the improved depressive symptoms (IDS) and no improvement in depressive symptoms (non-IDS) groups based on whether the HRSD score at 3 months was lower than at baseline. Neurological recovery at 3 months was assessed using the modified Rankin Scale (mRS). Results: The difference in DLMO between PSD and non-PSD patients was not statistically significant (p =0.173). In the non-IDS group, there was a significant decrease in melatonin secretion at 10 p.m. (p =0.012), and DLMO was significantly later than in the IDS group (p =0.017). Logistic regression analysis showed that DLMO (OR 1.91, 95%CI:1.13-3.23, p = 0.016) was an independent risk factor for persistent no improvement in depressive symptoms, which was associated with a markedly worse prognosis (p <0.001). Conclusion: Our findings suggest possible interventions for the very early identification of non- IDS patients.