The symptoms associated with drug abuse are generally both physical and behavioral, and can vary greatly depending upon the person and the type of drug being used. However, most drug addiction symptoms involve a noticeable change in attitude, appearance, or both. For example, changes in sleep patterns, eating habits, and energy levels are all common drug abuse symptoms. Many drug users suddenly acquire new friends, interests, and priorities, and develop problems performing well at work or in school. Drug users also tend to have dramatic changes in mood, becoming suddenly hostile, violent, or even depressed to the point of suicide. Some drugs will cause difficult-to-spot health problems, such as an erratic heartbeat, elevated blood pressure, or breathing difficulties, while others cause more obvious symptoms like dilated pupils, red eyes, or nosebleeds. In most cases, friends and family will be the first to notice the problem because they're more familiar with the individual's normal behavior. Fortunately, these are also the people who are in the best position to help someone with a drug addiction. For more information about the symptoms of drug abuse, consult a health care provider in your area.