Jakob Linnet1, 2, 3, 4, 5*
1Research clinic on Gambling Disorders, Aarhus University Hospital, Denmark
2Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
3Department of Nuclear Medicine & PET-Centre,, Aarhus University Hospital, Denmark
4Division on Addiction,, Cambridge Health Alliance, USA
5Department of Psychiatry, Harvard Medical School, USA
Gambling disorder sufferers prefer immediately larger rewards despite long term losses on the Iowa Gambling Task (IGT), and these impairments are associated with dopamine dysfunctions.
Dopamine is a neurotransmitter linked with temporal and structural dysfunctions in substance use disorder, which has supported the idea of impaired decision-making and dopamine dysfunctions in gambling disorder.
However, evidence from substance use disorders cannot be directly transferred to gambling disorder.
This article focuses on three hypotheses of dopamine dysfunctions in gambling disorder, which appear to be “fallacies”, i.e., have not been supported in a series of positron emission tomography (PET) studies.
- The first “fallacy” suggests that gambling disorder suffers, similar to substance use disorders, have lower dopamine receptor availability. No evidence supported this hypothesis.
- The second “fallacy” suggests that maladaptive decision-making in gambling disorder is associated with higher dopamine release during gambling. No evidence supported the hypothesis, and the literature on substance use disorders offers limited support for this hypothesis.
- The third “fallacy” suggests that maladaptive decision-making in gambling disorder is associated with higher dopamine release during winning. The evidence did not support this hypothesis either.
Instead, dopaminergic coding of reward prediction and uncertainty might better account for dopamine dysfunctions in gambling disorder. Studies of reward prediction and reward uncertainty shows a sustained dopamine response towards stimuli with maximum uncertainty, which may explain the continued dopamine release and gambling despite losses in gambling disorder. The findings from the studies presented here are consistent with the notion of dopaminergic dysfunctions of reward prediction and reward uncertainty signals in gambling disorder.
Keywords: gambling disorder, Iowa Gambling Task (IGT), Dopamine, Addiction, Positron-Emission Tomography
Citation: Linnet J (2013). The Iowa Gambling Task and the Three Fallacies of Dopamine in Gambling Disorder.. Front. Psychol. 4:709. doi: 10.3389/fpsyg.2013.00709
Received: 27 Jun 2013; Accepted: 17 Sep 2013.
Ching-Hung Lin, Kaohsiung Medical University, Taiwan
Wael Asaad, Brown University, USA
Eric E. Wassermann, NIH/NINDS, USA
Copyright: © 2013 Linnet. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Jakob Linnet, Aarhus University Hospital, Research clinic on Gambling Disorders, Nørrebrogade 44, Bldg. 30, Aarhus C, DK-8000, Denmark, [email protected]