Scientists have identified a failure in the formation of new neurons in depression

In people with depressive disorder, the process of forming new neurons in the hippocampus, an area of the brain associated with memory and emotional processing of events, may be disrupted. The scientists found that neural stem cells persisted, but their transformation into new neurons slowed down. The study was published on August 21 in the journal Nature Medicine.

The authors presented the largest multimodal atlas of adult hippocampal cells to date and studied the molecular changes accompanying major depressive disorder.

The main analysis covered about 495 thousand cell nuclei isolated from postmortem hippocampal samples of 11 people with depression and 19 participants in the control group. Additional verification methods were applied to samples from a wider group of donors. All participants with depression were not taking antidepressants at the time of death, which reduced the effect of drug therapy on the results.

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In people with depression, researchers have found more neural stem cells at an early stage of development, but fewer neuroblasts— the cells from which new neurons are formed. This does not mean that the stock of stem cells has disappeared, but that their further maturation has been disrupted.

The changes affected not only neurogenesis. In the cells of the hippocampus, scientists have identified signs of inflammation, cellular stress, impaired energy metabolism and signal transmission between neurons. The activity of genes responsible for the formation of new intercellular connections and brain plasticity also changed.

The head of the study, Maura Dupont, professor of psychiatry at Columbia University, suggested that restoring neurogenesis in the future may become one of the treatment areas for certain forms of depression. However, the work did not test drugs or other therapeutic methods.

The study was postmortem and simultaneous, so it shows a link between depression and disorders of neurogenesis, but does not prove that it was depression that stopped the formation of cells. The authors acknowledged that it is not yet possible to completely separate the changes associated with depression from the possible effects of suicidal behavior.

The cause of death, diseases, and other individual factors could also affect the condition of the tissues. Nevertheless, scientists believe that the results will help to more accurately identify the biological variants of depression and seek treatments focused on specific molecular disorders.

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