Recent studies (Redei) have shown that it’s not the neurotransmitters of serotonin, dopamine, and norepinephrine that cause or are related to depression, but rather it goes a layer deeper and it’s the actual neural pathways that are related.
Current research is very optimistic, because it turns out that the positive lifestyle changes advised for such a long time actually change both genetic expression and neural pathways. In other words, your brain cells listen to your behavior and beliefs, and if those behaviors and beliefs are powerful enough, the brain changes. What this means is that therapy, spiritual practices, healthy relationships, love and compassion, avoidance of toxins, meditation and stress management aren’t secondary. They are central to dealing with depression and anxiety.