Crystal meth is in the form of a rock-like crystal that uses heat and then smoke, although it can be snorted or injected. The short term effect of this drug when taken in large doses is erratic and even violent behavior. Other short-term effects of crystal meth include loss appetite, change in sleeping, elevated blood pressure, irregular heart rate. The long-term effects of this drug abuse can extremely affect the user like hallucinations, stroke, brain damage, a feeling of bugs crawling on the skin. Long lasting effects of crystal meth are violence, anorexia, and dental problems.