Department of Psychiatry, Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298-0126, USA.
Behav Genet. 2011 Jul;41(4):476-87. doi: 10.1007/s10519-010-9400-y. Epub 2010 Oct 2.
Depressive symptoms and alcohol use are frequently positively associated during adolescence. This study aimed to assess the heritability of each phenotype across adolescence; to assess potential shared liabilities; to examine changes in the nature of shared liabilities across adolescence; and to investigate potential causal relationships between depressive symptoms and alcohol use. We studied a longitudinally assessed sample of adolescent Finnish twins (N = 1,282) to test hypotheses about genetic and environmental influences on these phenotypes within and across ages, using data from assessments at ages 12, 14, and 17.5 years. The heritability of depressive symptoms is consistent across adolescence (~40-50%), with contributions from common and unique environmental factors. The heritability of alcohol use varies across time (a(2) = .25-.44), and age 14 alcohol use is heavily influenced by shared environmental factors. Genetic attenuation and innovation were observed across waves. Modest to moderate genetic (r(A) = .26-.59) and environmental (r(C) = .30-.63) correlations between phenotypes exist at all ages, but decrease over time. Tests for causal relationships between traits differed across ages and sexes. Intrapair MZ difference tests provided evidence for reciprocal causation in girls at ages 14 and 17.5. Formal causal models suggested significant causal relationships between the variables in both boys and girls. The association between depressive symptoms and alcohol use during adolescence is likely due to a combination of shared genetic and environmental influences and causal influences. These influences are also temporally dynamic, complicating efforts to understand factors contributing to the relationship between these outcomes.
抑郁症状和酒精使用在青少年时期经常呈正相关。本研究旨在评估每个表型在青少年时期的遗传力；评估潜在的共同局限性；检查青春期内共同局限性性质的变化；并研究抑郁症状和酒精使用之间潜在的因果关系。我们对芬兰青少年纵向评估的双胞胎样本（N=1,282）进行了研究，以使用 12、14 和 17.5 岁评估的数据，检验关于遗传和环境因素对这些表型的影响在年龄内和年龄间的假设。抑郁症状的遗传力在整个青春期内是一致的（~40-50%），由共同和独特的环境因素共同作用。酒精使用的遗传力随时间变化（a(2)=.25-.44），14 岁时的酒精使用受共同环境因素的影响很大。在各波次中观察到遗传衰减和创新。在所有年龄段，表型之间都存在适度到中度的遗传（r(A)=.26-.59）和环境（r(C)=.30-.63）相关性，但随着时间的推移而减少。在不同年龄和性别中，对特质之间因果关系的检验结果不同。同卵双胞胎 MZ 差异检验为 14 岁和 17.5 岁女孩的相互因果关系提供了证据。正式的因果模型表明，男孩和女孩的变量之间存在显著的因果关系。青少年时期抑郁症状和酒精使用之间的关联可能是由于共同的遗传和环境影响以及因果影响的结合所致。这些影响也是动态的，增加了理解导致这些结果之间关系的因素的复杂性。
