Only one study has examined bidirectional causality between sexual minority status (having same-sex attraction) and psychological distress. We combined twin and genomic data from 8700 to 9700 participants in the UK Twins Early Development Study cohort at ≈21 years to replicate and extend these bidirectional causal effects using separate unidirectional Mendelian Randomization-Direction of Causation models. We further modified these models to separately investigate sex differences, moderation by childhood factors (retrospectively-assessed early-life adversity and prospectively-assessed childhood gender nonconformity), and mediation by victimization. All analyses were carried out in OpenMx in R. Same-sex attraction causally influenced psychological distress with significant reverse causation (beta = 0.19 and 0.17; 95% CIs = 0.09, 0.29 and 0.08, 0.25 respectively) and no significant sex differences. The same-sex attraction → psychological distress causal path was partly mediated by victimization (12.5%) while the reverse causal path was attenuated by higher childhood gender nonconformity (moderation coefficient = −0.09, 95% CI: −0.13, −0.04).

只有一项研究检验了性少数身份（具有同性吸引力）与心理困扰之间的双向因果关系。我们结合了英国双胞胎早期发育研究队列中 8700 至 9700 名参与者的双胞胎和基因组数据，时间约为 21 年，使用单独的单向孟德尔随机化-因果关系方向模型复制和扩展这些双向因果效应。我们进一步修改了这些模型，以分别调查性别差异、童年因素的缓和（回顾性评估的早年逆境和前瞻性评估的童年性别不合格），以及受害的调解。所有分析均在 R 中的 OpenMx 中进行。同性吸引因果关系影响心理困扰，具有显着的反向因果关系（β = 0.19 和 0.17；95% CI = 0.09、0.29 和 0.08、0. 分别为 25)，并且没有显着的性别差异。同性吸引 → 心理困扰的因果路径部分由受害 (12.5%) 介导，而反向因果路径因较高的童年性别不合格而减弱 (调节系数 = −0.09, 95% CI: −0.13, −0.04)。