I think depression is the essence of having low state. When you're happy, and that is when you're actually happy and not just satisfied, you are at a high state. However, when you're less happy, you have a lower state. Essentially, having a low state of mind is being depressed. I personally can feel negative thoughts swimming around my head when I'm in a low state. When I'm in a high state, all I can feel is positivity. I can tell myself I'm amazing and immediately reaffirm it with a high state. When I'm at one of my lowest states, all I want is to not be seen.

I think happiness and depression is also linked to how tired your mind is. After I chug a boatload of caffeine, I not only feel active but I also feel positive thoughts and happiness swimming through me.