Impact of <i>DRD2/ANKK1</i> and <i>COMT</i> Polymorphisms on Attention and Cognitive Functions in Schizophrenia

<div><p>Background</p><p>Cognitive deficits such as poor selective attention and executive functions decline have been reported in patients with schizophrenia. Many studies have emphasized the role of dopamine in regulating cognitive functions in the general population as well as in schizophrenia. However, the relationship between cognitive processes, schizophrenia and dopaminergic candidate genes is an original approach given interesting results. The purpose of the current exploratory study was to examine the interaction of dopaminergic genes (coding for dopamine receptor D2, <i>DRD2</i>, and for Catecholamine-O-Methyl-Transferase, <i>COMT</i>) with the diagnostic of schizophrenia in (i) the executive control of attention, (ii) selective attention, and (iii) executive functions.</p><p>Methods and Results</p><p>We recruited 52 patients with schizophrenia and 53 healthy controls who performed the Stroop Color-Word Test, the Attention Network Test and the Wisconsin Card Sorting test. Four single nucleotide polymorphisms (SNPs) in the <i>DRD2</i> gene (rs6275, rs6277, rs2242592 and rs1800497) and two SNPs in the <i>COMT</i> gene (rs4680 and rs165599) have been genotyped. Patients with schizophrenia performed significantly worse than controls in all cognitive performance, taking into account demographic variables. A significant gene by disease interaction was found for the Stroop interference (p = 0.002) for rs6275 of the <i>DRD2</i> gene. The <i>COMT</i> Val/Val genotype and schizophrenia were associated with increased number of perseverative errors (p = 0.01).</p><p>Conclusions</p><p>In our study, the <i>DRD2</i> gene is involved in attention while the <i>COMT</i> gene is implicated in executive functions in patients with schizophrenia.</p></div

Association between genetic variants of <i>DRD2</i> genes and 6 cognitive scores (mean, SD) in 52 schizophrenia patients.

<p>Association between genetic variants of <i>DRD2</i> genes and 6 cognitive scores (mean, SD) in 52 schizophrenia patients.</p

rs6275 association with Stroop-PI latency score according to carried variant in 52 patients with schizophrenia and 53 healthy controls.

<p>rs6275 association with Stroop-PI latency score according to carried variant in 52 patients with schizophrenia and 53 healthy controls.</p

Association between genetic variants of <i>COMT</i> genes and 6 cognitive scores (mean, SD) in 52 schizophrenia patients.

<p>Association between genetic variants of <i>COMT</i> genes and 6 cognitive scores (mean, SD) in 52 schizophrenia patients.</p