Department of Psychology,University of Minnesota,75 East River Rd, Minneapolis, MN 55455,USA.
Institute of Child Development,University of Minnesota,51 E River Rd, Minneapolis, MN 55455,USA.
Psychol Med. 2018 Jul;48(10):1673-1684. doi: 10.1017/S0033291717003166. Epub 2017 Nov 7.
Although there is extensive evidence that problematic alcohol use is associated with smaller hippocampal volume, the typical cross-sectional study design cannot determine whether hippocampal deviations reflect pre-existing liability toward problematic alcohol use or instead reflect an alcohol exposure-related effect. We used the co-twin control study design, which capitalizes upon differences within a twin pair in levels of drinking, to differentiate pre-existing liability from an effect of alcohol exposure.
The sample included 100 female twins, prospectively assessed from ages 11 to 24. Problematic alcohol use was assessed dimensionally and included indicators of quantity, frequency, and density of alcohol use and intoxication. Hippocampal volume was assessed using magnetic resonance imaging.
Problematic alcohol use (proximal and cumulative) was associated with significantly smaller left and right hippocampal volume. Follow-up co-twin control analyses that partitioned individual-level alcohol effects into pre-existing, familial liability and non-shared alcohol exposure-related effects indicated that this association reflected alcohol exposure. Greater alcohol using twins had smaller hippocampal volume relative to lesser alcohol using co-twins, beyond effects of their shared genetic and environmental liability toward problematic alcohol use. Results held accounting for recent alcohol use, other substance use, externalizing and internalizing psychopathology, personality traits, trauma exposure, and menstrual phase.
The association between problematic alcohol use and smaller hippocampal volume likely reflects an alcohol exposure-related effect. Differentiating pre-existing brain deviations that confer risk for problematic alcohol use from those that reflect effects of alcohol on the brain will inform etiological models of addiction and further prevention and intervention efforts.
尽管有大量证据表明，问题性饮酒与海马体体积减小有关，但典型的横断面研究设计无法确定海马体的偏差是反映出对问题性饮酒的预先存在的易感性，还是反映出与酒精暴露相关的影响。我们使用同卵双胞胎对照研究设计，利用双胞胎在饮酒水平上的差异，将预先存在的易感性与酒精暴露的影响区分开来。
该样本包括 100 名女性双胞胎，从 11 岁到 24 岁进行前瞻性评估。问题性饮酒通过维度评估，包括饮酒量、频率和密度以及醉酒的指标。使用磁共振成像评估海马体体积。
问题性饮酒（近期和累积）与左、右海马体体积明显减小有关。后续的同卵双胞胎对照分析将个体水平的酒精效应分为预先存在的、家族易感性和非共享的与酒精暴露相关的效应，表明这种关联反映了酒精暴露。与较少饮酒的同卵双胞胎相比，饮酒较多的双胞胎的海马体体积更小，这超出了他们对问题性饮酒的共同遗传和环境易感性的影响。考虑到最近的饮酒、其他物质使用、外在和内在精神病理学、人格特质、创伤暴露和月经周期，结果仍然成立。
问题性饮酒与海马体体积减小之间的关联可能反映了与酒精暴露相关的影响。将预先存在的大脑偏差与那些反映酒精对大脑影响的偏差区分开来，将为成瘾的病因模型以及进一步的预防和干预措施提供信息。
