Brain activity differences between difficulty in falling asleep and early awakening symptoms in major depressive...

Numerous studies have revealed that patients with major depressive disorder (MDD) suffer from insomnia symptoms. However, the dysfunction pattern in specific insomnia symptoms in patients with MDD remains unclear. The present study aimed to examine the regional brain neuroimaging activity features of difficulty falling asleep (DFA) and early awakening (EA) in patients with MDD. The resting-fMRI by applying the amplitude of low-frequency fluctuation (ALFF) method was estimated in 50 MDD patients with DFA, 36 patients with EA, 46 patients without insomnia symptoms, and 60 matched healthy controls. The Pearson correlation analysis was used among the ALFF with significant difference brain regions, the 17-item Hamilton Depression Rating Scale factor scores, and the Pittsburgh Sleep Quality Index scores. Patients with DFA showed lower ALFF values in the left precentral gyrus than those with EA and higher ALFF values in the left insula than those without insomnia symptoms. Patients with EA showed higher ALFF values in the left precentral gyrus than those without insomnia symptoms. This study revealed distinct neural mechanisms underlying specific insomnia symptoms, identifying the left insula as a potential pathological region in DFA patients and the left precentral gyrus as a characteristic neuropathological region in EA patients.