CURRENT CONCEPTS OF ETHANOL DEPENDENCE

Alcohol dependence is considered to be divisible into two types (altho ugh the divisions between these are indistinct). These are psychologic al dependence, in which the rewarding effects of alcohol play a primar y role, and chemical dependence, in which adaptive changes in the brai n initiate punishing effects on withdrawal of alcohol, and suppression of these becomes the primary motive for using the drug. The neurochem ical basis for the rewarding effects of alcohol may be the potentiatio n of GABA at GABA(A) receptors (causing relaxation) and release of dop amine from mesolimbic neurones (causing euphoria). The adaptive change s which cause the alcohol withdrawal syndrome are not known for certai n, but alterations in GABA(A) receptors, NMDA receptors and voltage-op erated calcium channels all have a claim. However, it is distinctly do ubtful whether these all contribute to the negatively reinforcing effe cts of alcohol that are important in chemical dependence, although the y may be important in other pathological effects of alcohol abuse. Cur rent research badly needs better communication between basic scientist s and clinicians to establish research goals and to improve current mo dels.