This study involved an evaluation of two versions of the "premature aging" theory of chronic alcoholism: the accelerated aging and increased vulnerability versions. The major dependent measures used were the tests included in Reitan's brain age quotient (BAQ), a series of neuropsychological tests known to be sensitive to the effects of alcoholism and aging. Subjects were 40 chronic alcoholic inpatients and 40 matched controls, divided into age groups by decade, ranging from the 30s to the 60s. It was proposed that an interaction between age and presence or absence of alcoholism, with BAQ test differences between alcoholics and controls widening as age increases, would support the increased vulnerability version, while the absence of such an interaction would support the accelerated aging version. The results clearly favored the accelerated aging version, with marked BAQ test differences between alcoholics and controls appearing even in the 30-year-old groups. It was concluded that chronic alcoholics tend to perform at levels found for nonalcoholics 10 years their senior, but the discrepancy between alcoholics and nonalcoholics does not increase with age.