Drug addiction is a chronic neurobiological disease produced by repeated exposure to an addictive drug and characterized by loss of control over drug use. Complex neuroadaptations do not come about simply because of continued drug use, but as a result of complex interactions between drugs themselves and the circumstances in which they are taken. Thus, in vulnerable individuals, interaction between the drugs themselves and genetic, environmental, psychosocial, behavioral, etc., produces long-lived adaptations in the brain which explain the enduring effects of addiction. Non-substance or behavioral addiction (e. g. pathological gambling, food addiction, smartphone addiction) has been shown to have similarities to drug addiction. In this sense, the current Diagnostic and Statistical Manual has classified some of these disorders as impulse control disorders, a separate category from substance use disorders. Written by expert authors in the field, the purpose of this book is to offer a multidisciplinary view of addictive behaviour, including substance and behavioral addiction, to better understand the biological and psychological underpinnings of these disorders.