Catecholamine levels and delay discounting forecast drug use among African American youths.

AIMS: To test hypotheses about the contributions of the catecholamines epinephrine and norepinephrine [which serve as biological markers of life stress through sympathetic nervous system (SNS) activation], delay discounting and their interaction to the prediction of drug use among young African American adults.
DESIGN: A 1-year prospective study that involved assessment of SNS activity and collection of self-report data involving delay discounting and drug use.
SETTING: Rural communities in the southeastern United States. PARTICIPANTS: A total of 456 African Americans who were 19 years of age at the beginning of the study. MEASUREMENTS: At age 19, participants provided overnight urine voids that were assayed for epinephrine and norepinephrine. Participants were also assessed for hyperbolic temporal discounting functions (k) and drug use. At age 20, the participants again reported their drug use.
FINDINGS: Linear regression analyses revealed that (i) catecholamine levels at age 19 forecast increases in drug use [B = 0.087, P < 0.01, 95% confidence interval (CI) = 0.025, 0.148] and (ii) among young men, catecholamine levels interacted positively with delay discounting to forecast increases in drug use (simple slope = 0.113, P < 0.001, 95% CI = 0.074, 0.152).
CONCLUSIONS: Higher urinary catecholamine concentrations in their adulthood predict higher levels of drug use a year later among young African American men in the United States who engage in high, but not low, levels of delay discounting.