Dopamine changes in addiction

There is something of a paradox relating to the role of dopamine in addiction. Individuals with low levels of striatal dopamine receptors reported greater pleasurable effects from stimulant use than those with normal levels.^[1] However, the first of the markers of abnormal dopamine function in addiction discussed on the slide – that there are reduced numbers of dopamine receptors in the addicted brain – presents a challenge to the dopamine model of addiction.^[1] Because, if dopamine is responsible for the ‘high’ of drug use, then reduced receptor availability perhaps should result in less-rewarding drug effects.^[1]

Reference:
[1] Nutt DJ, Lingford-Hughes A, Erritzoe D, Stokes PR. The dopamine theory of addiction: 40 years of highs and lows. Nat Rev Neurosci 2015; 16 (5): 305–312.

[2] Goldstein RZ, Volkow ND. Drug addiction and its underlying neurobiological basis: neuroimaging evidence for the involvement of the frontal cortex. Am J Psychiatry 2002; 159 (10): 1642–1652.

[3] Volkow ND, Wang GJ, Fowler JS, et al. Addiction: beyond dopamine reward circuitry. Proc Natl Acad Sci USA 2011; 108 (37): 15037–15042.