Oral administration of 5‐hydroxytryptophan (5‐HTP) impairs decision making under ambiguity but not under risk: evidence from the Iowa Gambling Task

Abstract

Oral 5-HTP is psychoactive at low doses. Decisions made under ambiguity may be differentially sensitive to increased serotonin release or associated reductions in frontocortical dopamine activity.

Serotonin Transporter (5-HTTLPR) Genotype and Childhood Trauma are Associated with Individual Differences in Decision Making

“…In our relatively large sample, the mean probability of choosing a card from the “good” decks was below 50% for trials 1–19 and above 50% for all of the remaining 80 trials (i.e., trial 19 = 45% and trial 20 = 56%). Recent studies are consistent with this characterization as trials 1–20 representing ambiguity and trials 41–100 representing risk (Brand et al, 2007b;Gendle and Golding, 2010; Stoltenberg and Vandever, 2010). …”

“…There is some controversy regarding how much participants know about the response contingencies of each deck and when they know it (Brand et al, 2006). Although consensus has not yet been reached on how to define these two phases of decision making, emerging evidence suggests that at least in healthy adults only the first 20 trials should be considered ambiguity (Gendle and Golding, 2010; Stoltenberg and Vandever, 2010). …”

“…Altering the availability of serotonin by either acute depletion of its amino acid precursor tryptophan or by administration of the 5-HT precursor 5-Hydroxytryptamine can indicate the involvement of the 5-HT system in a given behavior. Acute tryptophan depletion reduces sensitivity to punishment-based information in decision making (Blair et al, 2008), and enhancing 5-HT availability impairs decision making under ambiguity, but not under risk (Gendle and Golding, 2010). Such findings implicate the 5-HT system in specific aspects of decision making and suggest that genes harboring polymorphisms that impact 5-HT availability are good candidates for further study.…”

Individual behavioral and neurochemical markers of unadapted decision-making processes in healthy inbred mice

“…It has been shown that 5-HT plays a key role during top-down control of decision-making (Van den Bos et al 2013) but some authors found that a low level of extracellular 5-HT is linked with poor performance during decision-making (Heitland et al 2012; Homberg et al 2008; Koot et al 2012; Pittaras et al 2013; Zeeb et al 2009) while others did not (Gendle et al 2010; Homberg et al 2008; Lage et al 2011; Macoveanu et al 2013; Stoltenberg et al 2011). Here, we observed that risky mice had a high level of 5-HT in the prelimbic (PrL), insular cortices (CIns) and a low level of 5-HT in the orbitofrontal cortex (OFC).…”

“…The COMT (catechol- O -methyltransferase) gene polymorphism leading to an increased level of endogenous dopamine, and serotonin transporter (5-HTTLPR) polymorphisms have been associated to decision-making impairments (Heitland et al 2012; Homberg et al 2008; Malloy-Diniz et al 2013). However, the results concerning 5-HT are somewhat contradictory (Gendle and Golding 2010; Heitland et al 2012; Homberg et al 2008; Koot et al 2012; Lage et al 2011; Macoveanu et al 2013; Pittaras et al 2013; Stoltenberg et al 2011; Zeeb et al 2009). …”