You may be hooked emotionally and psychologically. You may have a physical dependence, too. If you have a drug addiction, you have intense cravings for the drug. You want to use it again and again. When you stop taking it, you may have unpleasant physical reactions. While not everyone who uses drugs becomes addicted, many people do. Drug addiction involves compulsively seeking to use a substance, regardless of the potentially negative social, psychological and physical consequences. Certain drugs are more likely to cause physical dependence than are others.