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Updated: Apr 18, 2026
A General Method for Evaluating Deep Brain Stimulation Effects on Intravenous Methamphetamine Self-Administration
Published on: January 22, 2016
Low Dopamine D2/D3 Receptor Availability is Associated with Steep Discounting of Delayed Rewards in Methamphetamine
Michael E Ballard1, Mark A Mandelkern1, John R Monterosso1
1Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles (Drs Ballard, Ishibashi, Dean, and London); Department of Molecular and Medical Pharmacology, University of California Los Angeles (Robertson and Dr London); Brain Research Institute, University of California Los Angeles (Dr London); Veterans Affairs Greater Los Angeles Healthcare System, CA (Drs Ballard, Mandelkern, Ishibashi, and London and Robertson); Department of Physics, University of California Irvine, CA (Dr Mandelkern); Department of Psychology, University of Southern California, Los Angeles, CA (Dr Monterosso and Hsu).
Background:
Individuals with substance use disorders typically exhibit a predilection toward instant gratification with apparent disregard for the future consequences of their actions. Indirect evidence suggests that low dopamine D2-type receptor availability in the striatum contributes to the propensity of these individuals to sacrifice long-term goals for short-term gain; however, this possibility has not been tested directly. We investigated whether striatal D2/D3 receptor availability is negatively correlated with the preference for smaller, more immediate rewards over larger, delayed alternatives among research participants who met DSM-IV criteria for methamphetamine (MA) dependence.
Methods:
Fifty-four adults (n = 27 each: MA-dependent, non-user controls) completed the Kirby Monetary Choice Questionnaire, and underwent positron emission tomography scanning with [(18)F]fallypride.
Results:
MA users displayed steeper temporal discounting (p = 0.030) and lower striatal D2/D3 receptor availability (p < 0.0005) than controls. Discount rate was negatively correlated with striatal D2/D3 receptor availability, with the relationship reaching statistical significance in the combined sample (r = -0.291, p = 0.016) and among MA users alone (r = -0.342, p = 0.041), but not among controls alone (r = -0.179, p = 0.185); the slopes did not differ significantly between MA users and controls (p = 0.5).
Conclusions:
These results provide the first direct evidence of a link between deficient D2/D3 receptor availability and steep temporal discounting. This finding fits with reports that low striatal D2/D3 receptor availability is associated with a higher risk of relapse among stimulant users, and may help to explain why some individuals choose to continue using drugs despite knowledge of their eventual negative consequences. Future research directions and therapeutic implications are discussed.
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