However, the authors do admit to a few limits to their work. Their study didn't use people with a clinical diagnosis of depression, and the average level of depression in their participant pool was fairly mild, according to their evaluations. (They ruled out 15 participants from their dataset for antidepressant use, since it has been suggested to increase neurogenesis, the creation of neurons.) So it's hard to establish causation between depression, neurogenesis and pattern separation abilities. "We suggest that future research in this area is needed to better determine the type of relationships between psychological disorders, pattern separation, antidepressants, and neurogenesis," they write.