Tolerance means a person's body has adapted to a substance to the point that they need more and more of it in order to have the same reaction. With many drugs, the first use has a greater physical impact than any time afterward. That's why there is a tendency to increase their intake over time, to try and recapture that initial high. Tolerance is a common symptom of addiction but Compton says that just because someone has developed a tolerance, doesn't mean they're addicted.
Credit: Getty Images
Powered By ZergNet
The Brutal Charm of an NFL Hit Man
Plus: Jesse Ventura vs. the Navy Seals
ON NEWSSTANDS NOW
When to Say No to Your Doctor
Sign up to receive the Men’s Journal newsletter and special offers from MJ and its marketing partners.