New dissertation provides fascinating insights into how exercise and the antidepressant Lexapro have different but complementary antidepressant effects in the brain.

Karolinska Institutet – Exercise provides a clinical benefit for depressed patients comparable to that of antidepressants – this has been shown by previous research. Now Astrid Bjørnebekk at Karolinska Institutet has explained how and why this can happen: exercise not only stimulates the production of new brain cells, it enhances the integration of those new cells into functional neuronal networks – a feat that the SSRI escitalopram was unable to do by itself. This latter point was missed in the original press release for this research, but this enhanced neuronal integration is an important finding.

In a series of scientific experiments, Dr. Bjørnebekk has searched for the underlying biological mechanisms that explain why exercise can be a distinct “psychotropic” therapy for depression and has also compared its neurobiological effects with the effects of pharmacological treatment with an SSRI drug. She is, in effect, researching the “psychopharmacology of exercise.”

For those who wish to read the scientific details, a free summary of Dr. Bjørnebekk’s dissertation can be found online here:

On antidepressant effects of running and SSRIs: Focus on hippocampus and striatal dopamine pathways.

Abstracts from two of her published studies can be found here:

Antidepressant effect of running is associated with increased hippocampal cell proliferation

Effects of running on neuropeptide Y, opiates, and brain cell proliferation in an animal model of depression.

The experimental studies were conducted on rats. The results show that both exercise and antidepressants increase the formation of new cells in the hippocampus, which is an area of the brain important to memory and learning, and which can shrink in size during depression. Astrid Bjørnebekk’s studies show that the use of the SSRI escitalopram (Lexapro) in the absence of the “environmental enrichment” provided by running did not lead to a significant antidepressant response. Running, however, improved the treatment response, and appeared to regulate several brain chemicals important for full antidepressant response, such as neuropeptide Y and brain-derived neurotrophic factor (BDNF). Her study shows that exercise is a very good complement to psychotropic medications in this animal model of depression.

She states, “What is interesting is that the effect of antidepressant therapy can be greatly strengthened by external environmental factors,” such as exercise.