The results showed that the 861G allele of 5-HTR1B SNP rs6296 could significantly increase the risk of ADHD (C)R=1.09, 95% CI: 1.01-1.18); the 5-HTR2C gene rs518147 (OR=1.69, 95% CI: 1.38-2.07) and rs3813929 (OR = 1.57, 95% CI: 1.25-1.97) were all associated with the risk of ADHD.
The current study examined the association between adolescent outcome in ADHD and serotonin system genes, including the -1438A>G polymorphism of the serotonin 2A receptor gene (HTR2A) and the -759C>T polymorphism of the serotonin 2C receptor gene (HTR2C).
In our sample, the functional relevant 5-HTT promoter and the 5-HT2c receptor Cys23Ser polymorphism do not contribute to the supposed common genetic predisposition of ADHD and alcohol dependence.