The Nervous System and Addictions: Essentials for Clinicians

Understanding neurobiology forms a strong foundation for investigating addictive behavior. Brain structure is briefly discussed, including major cortical and subcortical structures, white matter pathways, other vital systems, and cellular components. The mesocorticolimbic system and dopamine are discussed in light of psychoactive substances. Mesocorticolimbic changes have been documented in the transition from recreational substance use to chronic dependence, reflecting a change from the basic positive reinforcement of initial use to the development of a negative reinforcement paradigm due to the avoidance of negative withdrawal consequences. Anticipation and craving reflect persistent changes in the mesolimbic system attributable to substance dependence. Not only do mesolimbic systemic operations alter in the presence of substances, but responses to substances within the structures themselves also appear to change. These principles are applied to the practical understanding of pathological compulsive behaviors, including gambling and hoarding, and the chapter then closes with a brief discussion of the societal value of insight into the neurological effects of substances.