Exosomes are associated with neuronal differentiation in mental disorders, such as depression. This study explored the effects of exosomes on neuronal differentiation and their underlying molecular mechanisms. We isolated exosomes from the sera of patients with depression. These characteristics were authenticated by TEM, NTA and western blotting. A differ-entiated cell model was established using all-trans retinoic acid (RA) to treat SH-SY5Y cells. Exosomes from depressed serum co-cultured with miR-96-5p mimic-transfected RA-treated cells, and PMA was used to activate RAC1. Neuronal differentiation indices were analyzedIP:by203.8.109.20microscopy,On:quantitativeWed, 03PCR,May 2023immunofluorescence10:21:32 assay, and western blotting. The results illustrated that exosomes inhibited RA-induced differiation, downregulated SYP, upregulated nestin, and Copyright: American Scientific Publishers decreased SYP-positive cell number. miR-96-5p was levated isrum-released exosomes from depressed patients, Delivered by In genta which impeded RA-induced neuronal differentiation. RAC1 is an miR-96-5p target. Activation of RAC1 partly counter-acted the effects on neuronal differentiation induced by enhanced miR-96-5p levels. Additionally, decreasing miR-96-5p attenuated depression-like behaviors and promoted hippocampal neuron differentiation induced by CUMS. Summarily, serum-derived exosomes from patients with depression suppress neuronal differentiation via the miR-96-5p/RAC1 axis. Moreover, decreased miR-96-5p levels suppresses CUMS-induced depression. These consequences suggest that regu-lating exosomes secretion and exosomal miR-96-5p expression will be a new approach for therapy of depression.