In the context of addiction, 'abuse' encompasses any use of illicit substances, excessive drinking or inappropriate use of medications, such as: taking larger doses than were prescribed or taking them for non medical reasons. In addition people can abuse inhalants (paint thinner, aerosol computer cleaners, air fresheners, hair spray, shoe polish, deodorant spray, etc.) by breathing in the fumes to get high.
Drug abuse might eventually lead to an addiction but, not everyone that uses drugs (or abuses them, for that matter) becomes addicted to them. There are various levels or stages of drug abuse problems and addiction. However, abuse always precedes addiction, and statistics bear out that many suffering from drug abuse do tend to progress to addiction.
Physicians have a medical definition of abuse that they use when they diagnose addictions. They divide the misuse of substances into two categories: substance abuse and substance dependency. In order to be diagnosed with substance abuse, a patient must have at least one of the following symptoms over a one-year period: The substance use results in a failure to fulfil work, school or home obligations; the substance use results in situations that are physically dangerous, such as drunk driving; the substance use precipitates legal problems; the person keeps using the substance even though he or she is experiencing social or interpersonal problems because of its use. The criteria for substance dependency are similar, but also include physical symptoms such as an increased ability to tolerate higher amounts of the substance and experiencing withdrawal symptoms when use is stopped.