What is craving? Models and implications for treatment.

Although many alcoholics experience craving, researchers have not yet developed a common, valid definition of the phenomenon. Numerous models of the mechanisms underlying craving have been suggested, however. One of those models—the neuroadaptive model—suggests that the prolonged presence of alcohol induces changes in brain-cell function. In the absence of alcohol, those changes cause an imbalance in brain activity that results in craving. Furthermore, the adaptive changes generate memories of alcohol’s pleasant effects that can be activated when alcohol-related environmental stimuli are encountered, even after prolonged abstinence, thereby leading to relapse. Similarly, stressful situations may trigger memories of the relief afforded by alcohol, which could also lead to relapse. Neurobiological and brain-imaging studies have identified numerous brain chemicals and brain regions that may be involved in craving. Psychiatric conditions that affect some of these brain regions, such as depression or anxiety, also may influence craving. A better understanding and more reliable assessment of craving may help clinicians tailor treatment to