Which substance is most commonly associated with sedation effects in users?

Alcohol is widely recognized for its sedative effects on the central nervous system. When consumed, alcohol enhances the action of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter that promotes relaxation and reduces neuronal excitability. This interaction leads to feelings of calmness, reduced anxiety, and sedation, making individuals feel more relaxed or drowsy.

In contrast, caffeine is a stimulant that typically increases alertness and energy levels rather than providing sedation. Cocaine and amphetamines are also stimulants associated with increased energy and alertness, leading to heightened activity and potential anxiety, rather than sedation. Therefore, alcohol stands out as the substance most commonly associated with sedative effects, making it the clear choice in this context.