Individual differences in personality, cognition, and behavior are impacted by genetic factors. Genes related to the dopamine and serotonin systems are believed to be most relevant to these facets due to their role in brain development, behavioral inhibition, and reward processing. The present study used an endophenotypic approach to assessing ADHD-related traits in a general sample of participants. Diagnoses for complex disorders such as ADHD are given to those who meet a threshold number of symptoms; by examining sub-syndromal quantitative traits, or endophenotypes, a more accurate assessment of genetic influence is fostered. This experiment investigated such characteristics of behavior, personality, and cognition as a function of DRD4, DAT1, 5HTT, and 5HTTLPR genotype. Informed consent was obtained by all participants. Participants in the study (n=160) were administered the Revised NEO Personality Inventory (NEO PI-R), Barrett Impulsivity Scale-11 (BIS), and Temperament and Character Inventory (TCI) to assess personality traits. They were also given computerized behavioral tests which assessed memory and attention. Polymerase chain reaction (PCR) and electrophoresis were performed to isolate and amplify the genes of interest. The data were examined for the relationship between personality traits and performance, with particular regard to attention and working memory.
Supported by Stony Brook University, GCRC grant #5-MO1-RR-10710, and the Simons Foundation.