{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T01:29:19Z","timestamp":1777858159759,"version":"3.51.4"},"reference-count":26,"publisher":"SAGE Publications","issue":"1","license":[{"start":{"date-parts":[[2003,1,1]],"date-time":"2003-01-01T00:00:00Z","timestamp":1041379200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Psychopharmacol"],"published-print":{"date-parts":[[2003,1]]},"abstract":"<jats:p>Choice behaviour can be viewed as a response to reinforcement determined by an interaction between the quantities, delays and probabilities of two outcomes. The variation in the perceived value of a reinforcer with alteration of these factors (discounting) can be modelled mathematically by hyperbolic discounting functions. Making risky choices is a feature of impulsivity and has been associated with reduced serotonin (5-hydroxytryptamine, 5-HT) function. In this study, we investigated the possible role of 5-HT in modulating probability discounting using the technique of acute tryptophan (TRP) depletion in subjects undertaking an imaginary gambling task. The gambling task consisted of choosing between two \u2018roulette-like\u2019 dials: \u2018A\u2019 which provided a smaller but nearly certain \u2018win\u2019 and \u2018B\u2019 which gave a \u2018win\u2019 2.5 times the amount with a probability that was systematically varied. A series of reward sizes on dial \u2018A\u2019 was presented ranging from 10 pence to \u00a310 000. The probability of winning on dial \u2018B\u2019 at which the subjects valued the two dials equally (indifference point) was determined as a measure of willingness to take a risk. Subjects were more likely to take a risk for smaller rewards but the indifference points in the 15 subjects who received TRP depletion did not differ from 13 who had the control drink. On a surprise retesting 1 week later there was a trend (p &lt; 0.07) for subjects to be more willing to take risks the second time, particularly in the case of small rewards. This study does not support a role for 5-HT in modulating probabilistic choice in agreement with recent evidence from experiments with animals; however, the imaginal nature of the task and modest numbers may have influenced the result.<\/jats:p>","DOI":"10.1177\/0269881103017001687","type":"journal-article","created":{"date-parts":[[2003,4,28]],"date-time":"2003-04-28T06:19:25Z","timestamp":1051510765000},"page":"3-7","source":"Crossref","is-referenced-by-count":29,"title":["The effect of acute tryptophan depletion on probabilistic choice"],"prefix":"10.1177","volume":"17","author":[{"given":"I. M.","family":"Anderson","sequence":"first","affiliation":[{"name":"Room G809, Stopford Building, Oxford Road, Manchester M13 9PL, UK,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R. A.","family":"Richell","sequence":"additional","affiliation":[{"name":"Institute of Cognitive Neuroscience, University College London, Alexandra House, London"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C. M.","family":"Bradshaw","sequence":"additional","affiliation":[{"name":"Psychopharmacology Section, Division of Psychiatry, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2003,1,1]]},"reference":[{"key":"atypb1","volume-title":"DSM-IV","author":"American Psychiatric Association","year":"1994","edition":"4"},{"key":"atypb2","doi-asserted-by":"publisher","DOI":"10.1001\/archpsyc.1961.01710120031004"},{"key":"atypb3","doi-asserted-by":"publisher","DOI":"10.1192\/bjp.178.5.399"},{"key":"atypb4","doi-asserted-by":"publisher","DOI":"10.1007\/PL00005485"},{"key":"atypb5","doi-asserted-by":"publisher","DOI":"10.1001\/archpsyc.1993.01820240059008"},{"key":"atypb6","doi-asserted-by":"publisher","DOI":"10.1037\/1064-1297.8.2.155"},{"key":"atypb7","doi-asserted-by":"publisher","DOI":"10.1192\/bjp.178.4.352"},{"key":"atypb8","volume-title":"Eysenck personality scales (EPS adult)","author":"Eysenck H J","year":"1991"},{"key":"atypb9","doi-asserted-by":"publisher","DOI":"10.1177\/026988119801200109"},{"key":"atypb10","doi-asserted-by":"publisher","DOI":"10.1007\/PL00005482"},{"key":"atypb11","doi-asserted-by":"publisher","DOI":"10.1177\/02698811000142S106"},{"key":"atypb12","doi-asserted-by":"publisher","DOI":"10.1093\/acprof:oso\/9780192620118.003.0014"},{"key":"atypb13","doi-asserted-by":"publisher","DOI":"10.3758\/BF03199051"},{"key":"atypb14","doi-asserted-by":"publisher","DOI":"10.1192\/bjp.176.2.182"},{"key":"atypb15","doi-asserted-by":"publisher","DOI":"10.1007\/s002130000542"},{"key":"atypb16","doi-asserted-by":"publisher","DOI":"10.1007\/PL00005480"},{"key":"atypb17","doi-asserted-by":"publisher","DOI":"10.1037\/0021-843X.110.3.482"},{"key":"atypb18","doi-asserted-by":"publisher","DOI":"10.1037\/0033-295X.93.1.33"},{"key":"atypb19","doi-asserted-by":"publisher","DOI":"10.1901\/jeab.1991.55-233"},{"key":"atypb20","doi-asserted-by":"publisher","DOI":"10.1006\/obhd.1994.1054"},{"key":"atypb21","doi-asserted-by":"publisher","DOI":"10.1901\/jeab.1999.71-121"},{"key":"atypb22","doi-asserted-by":"publisher","DOI":"10.1016\/S0893-133X(98)00091-8"},{"key":"atypb23","volume-title":"Consulting Psychologists Press","author":"Spielberger C D","year":"1970"},{"key":"atypb24","doi-asserted-by":"publisher","DOI":"10.1046\/j.1360-0443.1998.93689511.x"},{"key":"atypb25","doi-asserted-by":"publisher","DOI":"10.1176\/ajp.155.4.543"},{"key":"atypb26","doi-asserted-by":"publisher","DOI":"10.1007\/BF00431803"}],"container-title":["Journal of Psychopharmacology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/0269881103017001687","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/0269881103017001687","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T00:08:37Z","timestamp":1777507717000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/0269881103017001687"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2003,1]]},"references-count":26,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2003,1]]}},"alternative-id":["10.1177\/0269881103017001687"],"URL":"https:\/\/doi.org\/10.1177\/0269881103017001687","relation":{},"ISSN":["0269-8811","1461-7285"],"issn-type":[{"value":"0269-8811","type":"print"},{"value":"1461-7285","type":"electronic"}],"subject":[],"published":{"date-parts":[[2003,1]]}}}