Eighty percent of Individuals suffering from substance abuse also have a secondary diagnosis of depression and anxiety disorder. Individuals describe themselves as “feeling numb”. Natural forms of stimulation are “boring” against the vivid experience of the drug. As tolerance develops, it takes more and more of the drug to have the same initial intense “feeling.” Exercise increases the release of dopamine and endorphins produced by the body, and can have the same effect of a drug, producing a “natural high.” Many treatment centres now include exercise as an integral part of their programs.