Long ago I suffered some pretty bad depression and self-medicated with caffeine. I drank a lot of coffee in the morning and a lot of tea or diet soda in the afternoon. We're talking liters of it. It really did help immensely, but the cause of the depression was likely the lack of fat and protein in my diet. At the time I was my thinnest adult weight, I was cycling up a mountain or running every day and eating only vegetables, no meat, no carbs except what was in the vegetables, very little fat. Eventually I crashed and had to go on medication.
Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.