With AUD in the model with suicide and MDD, the effect of suicide remained and MDD became significant (F = 17.59, df = 1,313, p < 0.001), and there was an interaction between AUD and suicide (F = 31.427, df = 1,130, p < 0.001) with more 5-HT2A binding in suicides with AUD (Fig. 4b), but not in suicides without AUD. This evidence concerns the gene HTR2A and major depressive disorder.