Neukam PT, Kroemer NB, Deza Araujo YI, Hellrung L, Pooseh S, Rietschel M, Witt SH, Schwarzenbolz U, Henle T, Smolka MN. Risk-seeking for losses is associated with 5-HTTLPR, but not with transient changes in 5-HT levels.
Psychopharmacology (Berl) 2018;
235:2151-2165. [PMID:
29730700 DOI:
10.1007/s00213-018-4913-9]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
RATIONALE
Serotonin (5-HT) plays a key role in different aspects of value-based decision-making. A recent framework proposed that tonic 5-HT (together with dopamine, DA) codes future average reward expectations, providing a baseline against which possible choice outcomes are compared to guide decision-making.
OBJECTIVES
To test whether high 5-HT levels decrease loss aversion, risk-seeking for gains, and risk-seeking for losses.
METHODS
In a first session, 611 participants were genotyped for 5-HTTLPR and performed a mixed gambles (MGA) task and two probability discounting tasks for gains and losses, respectively (PDG/PDL). Afterwards, a subsample of 105 participants (44 with S/S, 6 with S/L, 55 with L/L genotype) completed the pharmacological study using a crossover design with tryptophan depletion (ATD), loading (ATL), and balanced (BAL) conditions. The same decision constructs were assessed.
RESULTS
We found increased risk-seeking for losses in S/S compared to L/L individuals at the first visit (p = 0.002). Neither tryptophan depletion nor loading affected decision-making, nor did we observe an interaction between intervention and 5-HTTLPR genotype.
CONCLUSION
Our data do not support the idea that transient changes of tonic 5-HT affect value-based decision-making. We provide evidence for an association of 5-HTTLPR with risk-seeking for losses, independent of acute 5-HT levels. This indicates that the association of 5-HTTLPR and risk-seeking for losses is mediated via other mechanisms, possibly by differences in the structural development of neural circuits of the 5-HT system during early life phases.
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