It is my experience that veganism inherently fights off depression and negative thoughts. By putting wholesome, natural foods into your body, you’re really doing good for the body, mind, and spirit. As Ellen DeGeneres said, by not putting animals in your body - and consequently the disease they suffer, as well as the fear they live in - you are rewarded with more positivity, reflected by your energy levels and resistance to illness.
To put it simple: Vegan is good.