Addiction (dependence on a particular substance or activity), is an important and complex area of mental health. Addiction can be difficult to treat, and there is a good deal of controversy surrounding the causes of addiction and the best approaches to treatment. Drug and alcohol abuse or misuse—excessive or inappropriate use of a substance—can be difficult to define, and people’s opinions, values, and beliefs vary significantly on the topic. For some, any use of an illegal drug or any use of alcohol with the primary purpose of intoxication constitutes abuse. For others, abuse is indicated by recurring, negative consequences, including: failure to meet social, work, and academic obligations; alcohol- or drug-related legal problems, such as arrest for driving while intoxicated; relationship problems with intimate partners, friends, and family.