It's wrong to become addicted to illegal drugs.
Mark has been using cocaine for several years and his health is deteriorating.
Mark wants to feel better.
Mark stops using cocaine and starts taking walks around the block instead.
Mark buys some more cocaine to take, so he can numb the pain and emptiness.
Mark's health takes a turn for the better and pretty soon he is in peak condition.
Mark's health gets worse and eventually he has to be sent to  the hospital.