Long-term alcohol self-administration with repeated alcohol deprivation phases: an animal model of alcoholism?

In order to study the neurobiological and molecular mechanisms of alcohol dependence and addiction, appropriate animal models are warranted. Although animal models cannot incorporate all aspects and criteria of an addictive behaviour to alcohol seen in human alcoholics, they can at least reflect some of the criteria given in the fourth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) of the American Psychiatric Association (1994). Novel aspects of addictive behaviour to alcohol, craving and relapse might be uncovered by animal models of long-term, free-choice, alcohol self-administration followed by alcohol deprivation phases. After several months of voluntary alcohol consumption, the drug-taking behaviour following a deprivation (withdrawal) phase is characterized by increased alcohol intake and preference (alcohol deprivation effect) and changes in alcohol intake patterns where animals consume large amounts of highly concentrated alcohol solutions even at inappropriate times (e.g. during the inactive light phase when drinking activity is minimal). Altogether, alcohol drinking following alcohol deprivation seems to become uncontrolled and inelastic, reflecting an incentive demand for the drug in such a model. Furthermore, the alcohol deprivation effect outlasts very long abstinence phases, which indicates the persistence of a drug memory for alcohol.