Wiström ED, O'Connell KS, Karadag N, et al. - Alcohol use disorder (AUD) is highly comorbid with schizophrenia (SCZ) and bipolar disorder (BD), and both comorbid AUD and excessive alcohol consumption (AC) have been associated with greater illness severity. In order to attain further insights into their shared genetic architecture, genomic loci jointly linked with SCZ, BD, AUD and AC are investigated herein.

• Using conjunctional false discovery rate (conjFDR) analysis, summary data (P values and Z scores) from genome-wide association studies (GWAS) were analyzed.

• Participants were AUD (34,658 cases, 167,346 controls), AC (n = 200,680), SCZ (31,013 cases and 38,918 controls), BD (20,352 cases and 31,358 controls).

• In conditional Q-Q plots, single-nucleotide polymorphism (SNP) enrichment was identified for both alcohol traits across various levels of significance with SCZ and BD, and vice versa.

• There appeared various loci shared between SCZ and AUD (n = 28) and AC (n = 24), BD and AUD (n = 2) and AC (n = 8) at conjFDR < 0.05.

• The share genomic loci had a mixed pattern of effect directions, indicating a complex genetic relationship between the phenotypes.