Relationship of DRD5 and MAO-B VNTR polymorphisms with paranoid and antisocial personality disorders in polydrug users.

Although multiple studies have shown the role genetics plays in personality disorders and in addictions, few have studied the genetic aspects of their comorbidity. Here, we carried out a cross-sectional study in a sample comprising 303 Caucasian polydrug-consuming patients. The presence of personality disorders was evaluated using the International Personality Disorder Examination, and genes related to dopamine, serotonin and monoamine oxidase (MAO) were genotyped. A significant relationship was observed between the bp 279 DRD5 variable number of tandem repeat (VNTR) polymorphism and paranoid personality disorder $\left(\text{OR}\left(95\%\mathrm{CI}\right)=2.186\left(1.074;4.449\right);p=0.006\right)$ . The bp 182 $\left(\text{OR}\left(95\%\mathrm{CI}\right)=0.407\left(0.178;0.931\right);p=0.033\right)$ and bp 184 $\left(\text{OR}\left(95\%\mathrm{CI}\right)=0.391\left(0.188;0.813\right);p=0.012\right)$ alleles of the MAOB VNTR were also associated with antisocial personality disorder. Among patients with addictions, paranoid personality disorder should also be considered in addition to the importance of antisocial and borderline personality disorders. The higher frequency of the bp 279 DRD5 VNTR allele found in patients with paranoid personality disorder, as well as the associations between alleles of the MAOB VNTR and antisocial personality disorder, support the monoaminergic bases of these personality disorders, especially when dealing with patients with addictions.