In some cases, when a person stops taking a drug, their body can have a lot of unpleasant symptoms. These symptoms may go away when the person uses the drug again. The other reason people misuse drugs has a lot to do with the effect of the drug on their mind and emotions. For many people, certain drugs seem to make them feel better mentally or emotionally. In some cases, starting with one drug can lead to the use of other drugs.
Some drugs require larger and larger amounts to produce the same effect.
Some people take additional drugs to help them reduce the unpleasant effects of the drugs they are already misusing. Eventually a person may take too much of a drug to feel the same effect. This can cause permanent medical damage or even the loss of life. Some drugs can be dangerous to take and some can be dangerous to stop without proper evaluation and treatment. Knowing why a person is using drugs is not as important as knowing what drugs the person is using, when they are taking drugs and how.