Craving for alcohol and drugs in animals and humans: Biology and behavior

Research studies indicate that sites and pathways for appetitive drive stat es, that are located in the limbic system, appear to be responsible for nor mal and pathological craving for alcohol and other addicting drugs. Patholo gical craving for alcohol and drugs in humans has been substantiated by ani mal studies, which have identified neurosubstrates and neurotransmitters as sociated with behavioral models of addiction. Repetitive administration of alcohol and drugs appears to affect hedonic homeostasis of the appetitive d rives leading to the hedonic alleostasis where negative reinforcement excee ds positive returns despite continued drug use. Neuroimaging studies have c oncentrated on areas in the brain related to reward or reinforcement of alc ohol/drug use, but the technique can be employed to find support for a neur osubstrate to distinguish normal craving or "liking" from pathological crav ing or "wanting" a drug. Identifying the neurobasis of "wanting" a drug lon g after not "liking it" is central to understanding pathological craving an d loss of control over drug use in addiction in humans. Neuroimaging is cur rently the only method to directly visualize sites for craving in the brain in humans. Neuroimaging techniques will provide methods, which are not pos sible in animals, for studying addictive disease in humans. (C) 2001 by The Haworth Press, Inc . All rights reserved.