Mechanisms of the psychostimulant effects of caffeine: implications for substance use disorders.
Level 5 - mechanism / opinion, no new human data
Narrative review and mechanistic model based on preclinical and bench pharmacology.
PubMed 26786412 · doi:10.1007/s00213-016-4212-2
What was done
Narrative review evaluating the neuropharmacological mechanisms underlying caffeine's psychostimulant, reinforcing, and arousing effects compared to prototypical psychostimulants. The authors synthesized mechanistic evidence to propose a model centered on the striatal adenosine A2A-dopamine D2 receptor heteromer.
What was found
The abstract contains no quantitative metrics, effect estimates, or statistical data. Mechanistically, caffeine is described as removing the inhibitory brake that endogenous adenosine exerts on ascending dopamine and arousal pathways via striatal A2A-D2 receptor heteromers. This framework accounts for caffeine-induced rotational behavior and reversal of the adipsic-aphagic syndrome in rodent models, explains its relatively low direct abuse liability, and models its ability to potentiate the addictive and toxic effects of other drugs of abuse (e.g., cocaine, amphetamines, synthetic cathinones, and alcohol).
Why it matters
It offers a mechanistic receptor-heteromer model explaining how caffeine, despite low intrinsic addiction liability, can enhance the reinforcing and toxic properties of co-ingested psychostimulants and drugs of abuse.
Limits
This is a narrative review presenting theoretical and preclinical mechanistic models without systematic review methodology. No original human trial data, sample sizes, or quantitative measures are reported in the abstract, limiting direct extrapolation to clinical human populations.
Cited by
- supports Caffeine works by blocking adenosine receptors in the body and brain.