Table 1.

The main effects of caffeine action on the nervous system and the most likely mechanisms of its action.

Disease/Disorder	Mechanism	Effect
Alzheimer’s disease	↓ Aβ generation, activation of ARs, antioxidant activity	↓ risk of disease [45,50,97]
Parkinson’s disease	Activation of ARs	↓ risk of disease [47,51,98]
Huntington’s disease	Unknown	↑ risk of disease [57]
Depression	Antagonism of ARs	↓ risk of disease [45,96,102]
Mood	Antagonism of ARs, inhibition of AChE, impact on RyRs	stimulation at low doses [8,27] ↑ restlessness, excitement, tremor, tinnitus, headache, and insomnia at high doses [30,34] ↑ anxiety [94,95,96]

Aβ—amyloid beta, Ars—adenosine receptors, AChE—acetylcholinesterase, RyRs—ryanodine receptors. ↓—decrease, ↑—increase.