REVIEWSA review of delay-discounting research with humans: relations to drug use and gamblingReynolds, BradyAuthor Information Department of Pediatrics, Columbus Children's Research Institute, The Ohio State University, Columbus, Ohio, USA Correspondence and requests for reprints to Dr Brady Reynolds, The Ohio State University, 700 Children's Drive, J1401, Columbus, OH 43205, USA E-mail: ReynoldB@pediatrics.ohio-state.edu Sponsorship: This work was supported in part by a grant from the National Institute on Drug Abuse (R21 DA020423). Received 27 February 2006 Accepted as revised 28 September 2006 Behavioural Pharmacology: December 2006 - Volume 17 - Issue 8 - p 651-667 doi: 10.1097/FBP.0b013e3280115f99 Buy Metrics Abstract Delay discounting represents the extent to which consequences, or outcomes, decrease in effectiveness to control behavior as a function of there being a delay to their occurrence. Higher rates of delay discounting are often operationalized as an index of impulsivity, and as such impulsive discounting may hold considerable potential for understanding fundamental behavioral processes associated with a range of problematic behaviors – including drug use and pathological gambling. This paper first provides a review of several assessment methods used in delay-discounting research with humans. Following, the delay-discounting literature related to drug use and gambling is reviewed. Consistencies across this literature are identified; and future research directions are discussed, which include (a) improving methods of assessment for delay discounting and (b) moving drug-use research progressively to causal interpretations, with high rates of delay discounting either predisposing to drug use or resulting from drug use itself. © 2006 Lippincott Williams & Wilkins, Inc.