Dopamine D2/D3 receptor availability and working memory in stimulant use disorder.

Area of Science:

• Neuroscience
• Psychiatry
• Addiction Medicine

Background:

• Dopaminergic neurochemical markers correlate with working memory in healthy individuals and schizophrenia patients.
• Individuals with stimulant use disorder exhibit reduced dopaminergic markers, including striatal D2/3 receptor availability, and impaired working memory.

Purpose of the Study:

• To investigate the relationship between working memory performance and D2/3 receptor availability in individuals with stimulant use disorder.
• To inform the development of targeted treatments for stimulant use disorder.

Main Methods:

• Eighty-four adults with stimulant use disorder and 47 controls completed the Spatial Capacity Delayed Response Task (SCAP) for working memory assessment.
• A subset of the stimulant use disorder group (n=52) underwent positron emission tomography (PET) using [18F]fallypride to measure D2/3 receptor availability.
• Correlations between SCAP performance and D2/3 receptor availability were analyzed in key cortical regions.

Main Results:

• Participants with stimulant use disorder showed significantly poorer performance on the SCAP compared to controls, even after controlling for demographics and intelligence.
• In the stimulant group, SCAP performance positively correlated with D2/3 receptor availability in the cingulate cortex (p < .013).

Conclusions:

• The observed working memory deficits in stimulant use disorder are associated with reduced cortical D2/3 receptor signaling.
• Therapeutic strategies aimed at enhancing cortical D2/3 receptor signaling could potentially improve cognitive function and treatment response in this population.