Early and late onset, first-episode, treatment-naive depression: same clinical symptoms, different regional neural activities.

Background: Patients with early onset depression (EOD) and late onset depression (LOD) have distinctive risk factors and clinical pictures. Using regional homogeneity (ReHo) approach, we were to test the hypothesis of the different abnormal neural activity between patients with EOD or LOD.

Methods: Fifteen patients with EOD, 15 patients with LOD, 15 young healthy subjects (HS) and 15 old HS participated in the study. ReHo approach was employed to analyze the scans.

Results: ANOVA analysis revealed widespread differences in ReHo values among the four groups throughout frontal, parietal, temporal, occipital cortex, cerebellum and limbic regions. Compared to LOD group, EOD group had higher ReHo in right precuneus (PCu) and bilateral superior frontal gyrus, and lower ReHo in left superior temporal gyrus. Compared to young HS, lower ReHo in left parahippocampal gyrus and higher ReHo in left fusiform gyrus and bilateral superior frontal gyrus were seen in EOD group; in contrast, in LOD group, lower ReHo in right PCu and higher ReHo in left superior temporal gyrus and left Crus I of the cerebellum were observed. Further ROC analysis suggested that the mean ReHo values in right PCu and bilateral superior frontal gyrus could serve as markers to identify patients with EOD from individuals with LOD.

Limitation: The large age gap may limit the translational value of our findings.

Conclusions: Patients with EOD and those with LOD have abnormal neural activities in different brain regions, although the two groups share the same symptoms.