Carmine M. Pariante, M.D., Ph.D., Professor of Biological Psychiatry at King’s College London’s Institute of Psychiatry, is one of the authors of a new study that identifies the signaling pathway in the brain that, when affected by high levels of the stress hormone cortisol, can reduce  the brain’s ability to produce new cells. Other recent research has demonstrated that depression is associated with a reduction in this brain process, called “neurogenesis,” but the pathway responsible for the process has, until now, remained unknown.

Dr. Pariante received 2003 and 2005 NARSAD Young Investigator Grants—one of three types of research grants funded by the Brain & Behavior Research Foundation. He and his fellow researchers at King’s College reported that they found that high concentrations of cortisol harmed the stem cells of the animals they tested and resulted in a reduction in new-born brain cells. Through their experiments, the research team determined where in the brain this process takes place and named the signaling mechanism the “Hedgehog pathway.”

It is hoped that this new research will lead to faster and more effective treatments for depression, which affects seven percent of the U.S. population. The results of the new study were published online in the journal Neuropharmacology on December 6, 2012.

Dr. Christoph Anacker,  lead author of the study, said the findings are important because: "By decreasing the number of new-born cells in the human brain, stress hormones damage many important brain functions and may contribute to the development of depression after a period of chronic stress … With as much as half of all depressed patients failing to improve with currently available treatments, developing new, more effective antidepressants still remains a great challenge, which makes it crucial to identify new potential mechanisms to target. The discovery of antidepressants has so far been mainly by serendipity. Developing a drug with a defined effect on the brain, such as increasing the number of new-born brain cells, and with a clear target, such as Hedgehog signaling, will allow us to develop much more specific antidepressants in the future."

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