This study investigates the effect of chronic antidepressant treatment on hippocampal neurogenesis in adult rats using bromodeoxyuridine (BrdU) as a marker for dividing cells. The results show that chronic antidepressant administration significantly increases the number of BrdU-labeled cells in the dentate gyrus and hilus of the hippocampus. This increase is observed after chronic, but not acute, treatment, consistent with the time course for the therapeutic action of antidepressants. Additionally, the study demonstrates that antidepressant treatment increases the proliferation of hippocampal cells, which mature and differentiate into neurons. These findings suggest that increased cell proliferation and neuronal number may be mechanisms by which antidepressants overcome stress-induced atrophy and loss of hippocampal neurons, contributing to their therapeutic effects. The study also highlights the potential role of neurotrophic factors such as brain-derived neurotrophic factor (BDNF) in regulating neurogenesis and the therapeutic actions of antidepressants.This study investigates the effect of chronic antidepressant treatment on hippocampal neurogenesis in adult rats using bromodeoxyuridine (BrdU) as a marker for dividing cells. The results show that chronic antidepressant administration significantly increases the number of BrdU-labeled cells in the dentate gyrus and hilus of the hippocampus. This increase is observed after chronic, but not acute, treatment, consistent with the time course for the therapeutic action of antidepressants. Additionally, the study demonstrates that antidepressant treatment increases the proliferation of hippocampal cells, which mature and differentiate into neurons. These findings suggest that increased cell proliferation and neuronal number may be mechanisms by which antidepressants overcome stress-induced atrophy and loss of hippocampal neurons, contributing to their therapeutic effects. The study also highlights the potential role of neurotrophic factors such as brain-derived neurotrophic factor (BDNF) in regulating neurogenesis and the therapeutic actions of antidepressants.