What is Addiction?
This section defines addiction as a chronic relapsing disorder characterized by compulsive drug seeking, a loss of control in limiting intake, and emergence of a negative emotional state when access to the drug is prevented. The definition of addiction is derived from the evolution of the concept of dependence and the nosology of addiction diagnosis. A distinction is made between drug use and substance use disorders (formerly abuse and dependence). Addiction affects a large percentage of society and has enormous monetary costs. Addiction evolves over time, moving from impulsivity to compulsivity and ultimately being composed of three stages: preoccupation/anticipation, binge/intoxication, and withdrawal/negative affect. Motivational, psychodynamic, social psychological, and vulnerability factors all contribute to the etiology of addiction, but this book focuses on the neuroadaptational changes that occur during the addiction cycle. A theoretical construct is described that derives from early homeostatic theories and subsequent opponent process theories to provide a basis for understanding the neurobiology of addiction. This three-stage cycle framework is followed in each section for each major drug class (Psychostimulants, Opioids, Alcohol, Nicotine, and Cannabis).