That article is all over the place with it's verbage and intention. What it is actually saying is that there was a meta study done that found low serotonin its

That article is all over the place with it's verbage and intention. What it is actually saying is that there was a meta study done that found low serotonin itself was not necessarily the cause of depression. However drugs that target serotonin still work as anti-depressants. It's really a terrible article. Never mind using "chemical imbalance" and "low serotonin" interchangeably throughout the article.