Note: Single-source report; awaiting corroboration.
Depression is a common mental health condition linked to a tendency to focus on negative memories and information. Researchers examined how neurogenesis, the process of generating new neurons, may differ in people with depression by studying the hippocampus, a brain region crucial for memory.
In a study published in Nature Medicine, researchers analyzed hippocampal tissue from 19 donors without depression and 11 with depression, none of whom had taken antidepressants in the three months prior to death. They examined gene activity in about half a million hippocampal cells to identify changes associated with depression.
The findings showed that tissue from individuals with depression contained more neural stem cells and fewer intermediate cells transitioning toward maturity, compared to tissue from those without depression. This suggests a possible stall in the development from stem cells to intermediate neurons in depression. Despite these differences, the total number of neurons was similar between both groups, indicating that new neurons make up a small portion of all hippocampal neurons.
Additionally, gene expression analysis revealed differences in brain cells from people with depression, including genes involved in immune system function and stress responses. Some of these genes have been associated with depression, Alzheimer’s disease, and inflammatory conditions such as lupus and long COVID, which can also present with depression-like and cognitive symptoms.