"Highs" can come from drugs, alcohol, or even doing things like shopping, gambling, and other equally bad habits. "Good" highs come from things like eating right, exercise (runner's high) and those types are good for you. But regardless, just know that those types of things are not the cure for bad emotions; they merely cover them for a moment.
We reflect what we believe and it shows in our emotions. (This is something to consider when raising children, to give them a strong positive belief system, to help them to grow into strong, healthy, and adaptable adults.)