Abstract
Backgrounds
Cigarette smoking is strongly associated with major depressive disorder (MDD). However, any genetic etiology of such comorbidity and causal relations is poorly understood, especially at the genome-wide level.
Methods
In the present in silico research, we analyzed summary data from the genome-wide association study of the Psychiatric Genetic Consortium for MDD (n = 191 005) and UK Biobank for smoking (n = 337 030) by using various biostatistical methods including Bayesian colocalization analysis, LD score regression, variant effect size correlation analysis, and Mendelian randomization (MR).
Results
By adopting a gene prioritization approach, we identified 43 genes shared by MDD and smoking, which were significantly enriched in membrane potential, gamma-aminobutyric acid receptor activity, and retrograde endocannabinoid signaling pathways, indicating that the comorbid mechanisms are involved in the neurotransmitter system. According to linkage disequilibrium score regression, we found a strong positive correlation between MDD and current smoking (rg = 0.365; p = 7.23 × 10−25) and a negative correlation between MDD and former smoking (rg = −0.298; p = 1.59 × 10−24). MR analysis suggested that genetic liability for depression increased smoking.
Conclusions
These findings inform the concomitant conditions of MDD and smoking and support the use of self-medication with smoking to counteract depression.
TAIL-seq: Genome-wide Determination of Poly(A) Tail Length and 3′ End Modifications
