BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is often accompanied by impaired response inhibition; both have been associated with aberrant dopamine signalling. Given that prenatal exposure to alcohol or smoking is known to affect dopamine-rich brain regions, we hypothesized that individuals carrying the ADHD risk alleles of the dopamine receptor D4 (DRD4) and dopamine transporter ...

Recent studies as well as theoretical models of error processing assign fundamental importance to the brain's dopaminergic system. Research about how the electrophysiological correlates of error processing--the error-related negativity (ERN) and the error positivity (Pe)--are influenced by variations of common dopaminergic genes, however, is still relatively scarce. In the present study, we the...

Smaller total brain and subcortical volumes have been linked to psychopathology including attention-deficit/hyperactivity disorder (ADHD). Identifying mechanisms underlying these alterations, therefore, is of great importance. We investigated the role of gene-environment interactions (GxE) in interindividual variability of total gray matter (GM), caudate, and putamen volumes. Brain volumes were...

BACKGROUND Impairments in working memory are present in many psychiatric illnesses such as attention-deficit hyperactivity disorder (ADHD) and schizophrenia. The dopamine transporter and catechol-O-methyltransferase (COMT) are proteins involved in dopamine clearance and the dopamine system is implicated in the modulation of working memory (WM) processes and neurochemical models of psychiatric d...

Previous studies have found heterogeneous association between DAT1-3'-UTR-VNTR and attention deficit hyperactivity disorder (ADHD). Various proportions of conduct disorder (CD) comorbidity in their ADHD samples may partially explain the observational discrepancies. Evidence for this comes from family and twin studies which found ADHD probands with CD (ADHD + CD) are genetically different from t...

1 Knowledge about the functional status of the frontal cortex in infancy is limited. This study 2 investigated the effects of polymorphisms in four dopamine system genes on performance in 3 a task developed to assess such functioning, the Freeze-Frame task, at 9 months of age. 4 Polymorphisms in the catechol-O-methyltransferase (COMT) and the dopamine D4 receptor 5 (DRD4) genes are likely to im...

Functional polymorphisms in the dopamine transporter gene (DAT1 or SLC6A3) modulate responsiveness to salient stimuli, such that carriers of one 9R-allele of DAT1 (compared with homozygote carriers of the 10R-allele) show heightened reactivity to drug-related reinforcement in addiction. Here, using multimodal neuroimaging and behavioral dependent variables in 73 human cocaine-addicted individua...

Treatment with second-generation antipsychotics (SGAs) can cause obesity and other cardiometabolic disorders linked to D2 receptor (DRD2) genotypes affecting dopaminergic (DA) activity, within reward circuits. We explored the relationship of alterations single genetic polymorphisms DRD2 rs1799732 (NG_008841.1:g.4750dup -> C), rs6277 (NG_008841.1:g.67543C>T), COMT rs4680 (NG_011526.1:g.270...

We have attempted to identify regions involved in the transcriptional regulation of the DAT1 (HUGO approved symbol SLC6A3) gene that may harbor functional variants predisposing to several neuropsychiatric disorders by examining haplotypes of various 5' and intronic regions for their effect on expression in a dopaminergic cell line. A 1.5-fold difference in regulatory activity was observed betwe...

OBJECTIVE Attention-deficit/hyperactivity disorder (ADHD) has been linked to deficits in the dopaminergic reward-processing circuitry; yet, existing evidence is limited, and the influence of genetic variation affecting dopamine signaling remains unknown. We investigated striatal responsivity to rewards in ADHD combined type (ADHD-CT) using functional magnetic resonance imaging (fMRI), and wheth...