Unlike studies assessing brain atrophy, however, neuropsychological investigations have not accumulated much support for either version of the premature aging hypothesis. Results of a few studies favor the increased vulnerability hypothesis, but the evidence is inconsistent (for reviews, see Ellis and Oscar-Berman 1989; Evert and Oscar-Berman 1995). In support of the hypothesis, one study demonstrated that on the parts of IQ tests that normally pose difficulties for elderly nonalcoholic people, alcoholics between the ages of 48 and 74 performed significantly worse than same-age nonalcoholic control subjects and younger alcoholics (Ellis 1990). The increased vulnerability hypothesis leads to a second prediction, however, which was not supported by the study.
