Although there are a few different ways to define and use this term, in this case we are talking about tolerance as it relates to drugs. When you take medications or drugs your body begins to get used to the drug. As a result, you may need to take more and more of it in order to get the same effects. This reduced effect of the drug is tolerance - your body is getting used to the drug causing a reduction in its effectiveness. In some cases, psychologists require patients to go without medications or take breaks from their medications (drug holidays) in order to reduce tolerance and maintain its effectiveness.