Neurobiological Theories of Addiction: A Comprehensive Review

It is essential to develop theories and models that enable us to understand addiction’s genesis and maintenance, providing a theoretical and empirical framework for designing more effective interventions. Numerous clinical and preclinical research studies have investigated the various brain and physiological mechanisms involved in addictive behavior. Some researchers have gone a step further, developing what we may refer to as “neurobiological theories of addiction”, which are scientific models that can explain and predict different addiction phenomena. Many of these neurobiological theories are not mutually exclusive but rather extensions and refinements of earlier theories. They all share a similar definition of addiction as a chronic disease characterized by a loss of control over substance consumption, with the brain being identified as the principal organ involved. Most propose a multifactorial causation in which both biological and environmental factors interact, accentuating or causing neurobiological dysfunction in structures and brain circuits involved in behavior and motivation. This review delves into primary neurobiological theories of addiction, commencing with the opponent-process theory—one of the earliest comprehensive explanations of the addictive process. Subsequently, we explore more contemporary formulations connecting behavioral alterations in the addictive process to changes and disruptions in various brain systems.