Since drug abuse can have devastating consequences, it's important for friends and family to recognize the symptoms of a drug problem. Many experts agree that early detection and intervention can greatly reduce the chances of a life-long addiction. People abusing drugs often exhibit a variety of behavioral signs. These signs typically involve a prolonged change in mood, which may include irritability, depression, secretiveness, hostility, and unpredictability. A decrease in responsibility, such as missing work or school, or forgetting family occasions can also be a warning sign. In addition, drug abuse often leads to a sudden change in friends or hobbies. Other behavioral changes may include problems with communication, physical and mental deterioration, and unprovoked outbursts. If excessive drug use continues, the person can become more demanding and intolerable, and may even commit crimes or attempt suicide. Fortunately, there are a number of successful drug treatment programs available to help abusers cope with their problems. For more information about behavioral signs of drug abuse, consult a local health care professional.