Department of Child and Adolescent Psychiatry, Institute of Psychiatry and Mental Health, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), CIBERSAM, Hospital General Universitario Gregorio Marañón, Madrid, Spain
Department of Child and Adolescent Psychiatry, Institute of Psychiatry and Mental Health, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), CIBERSAM, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
BMJ Ment Health. 2023 Nov 24;26(1):e300821. doi: 10.1136/bmjment-2023-300821.
Despite the evidence supporting the relationship between socioeconomic status (SES) and severe mental disorders (SMD), the directionality of the associations between income or education and mental disorders is still poorly understood.
To investigate the potential bidirectional causal relationships between genetic liability to the two main components of SES (income and educational attainment (EA)) on three SMD: schizophrenia, bipolar disorder (BD) and depression.
We performed a bidirectional, two-sample univariable Mendelian randomisation (UVMR) and multivariable Mendelian randomisation (MVMR) study using SES phenotypes (income, n=397 751 and EA, n=766 345) and SMD (schizophrenia, n=127 906; BD, n=51 710 and depression, n=500 119) genome-wide association studies summary-statistics to dissect the potential direct associations of income and EA with SMD.
UVMR showed that genetic liability to higher income was associated with decreased risk of schizophrenia and depression, with a smaller reverse effect of schizophrenia and depression on income. Effects were comparable after adjusting for EA in the MVMR. UMVR showed bidirectional negative associations between genetic liability to EA and depression and positive associations between genetic liability to EA and BD, with no significant effects on schizophrenia. After accounting for income, MVMR showed a bidirectional positive direction between genetic liability to EA and BD and schizophrenia but not with depression.
Our results suggest a heterogeneous link pattern between SES and SMD. We found a negative bidirectional association between genetic liability to income and the risk of schizophrenia and depression. On the contrary, we found a positive bidirectional relationship of genetic liability to EA with schizophrenia and BD, which only becomes apparent after adjusting for income in the case of schizophrenia.
These findings shed light on the directional mechanisms between social determinants and mental disorders and suggest that income and EA should be studied separately in relation to mental illness.
尽管有证据表明社会经济地位（SES）与严重精神障碍（SMD）之间存在关联，但收入或教育与精神障碍之间关联的方向性仍知之甚少。
研究 SES 的两个主要组成部分（收入和受教育程度（EA））的遗传易感性与三种 SMD（精神分裂症、双相情感障碍（BD）和抑郁症）之间潜在的双向因果关系。
我们使用 SES 表型（收入，n=397751；EA，n=766345）和 SMD（精神分裂症，n=127906；BD，n=51710 和抑郁症，n=500119）全基因组关联研究汇总统计数据，进行了双向、两样本单变量 Mendelian 随机化（UVMR）和多变量 Mendelian 随机化（MVMR）研究，以剖析收入和 EA 与 SMD 之间潜在的直接关联。
UVMR 表明，较高收入的遗传易感性与精神分裂症和抑郁症的风险降低有关，而精神分裂症和抑郁症对收入的反向影响较小。在 MVMR 中调整 EA 后，结果相当。UMVR 显示遗传易感性 EA 与抑郁症之间存在双向负相关，与 BD 之间存在正向相关，与精神分裂症无显著相关。在考虑收入后，MVMR 显示遗传易感性 EA 与 BD 和精神分裂症之间存在双向正相关，但与抑郁症无关。
我们的研究结果表明 SES 和 SMD 之间存在异质的联系模式。我们发现收入遗传易感性与精神分裂症和抑郁症风险之间存在负向双向关联。相反，我们发现遗传易感性 EA 与精神分裂症和 BD 之间存在正向双向关系，只有在考虑收入的情况下，这种关系在精神分裂症中才变得明显。
这些发现揭示了社会决定因素与精神障碍之间的方向性机制，并表明在研究精神疾病时，应分别研究收入和 EA。
