Reverse Tolerance

When a drug is repeatedly administered, tolerance may develop to certain effects of the drug so that larger doses are needed to achieve the same effects. Reverse tolerance, also known as sensitization or behavioral sensitization, occurs when an effect of a drug increases with repeated administration. Reverse tolerance occurs less frequently than tolerance and happens only with particular effects of certain drugs. Reverse tolerance is not fully understood, but most of the research in this area focuses on the stimulating effects of drugs such as cocaine, amphetamines, and alcohol. These drugs produce activating effects in the dopaminergic system of the brain and effect the behavior of animals and humans; even when low doses are repeatedly administered, there is a progressive increase in activation with each ...