How does amphetamines cause wakefulness and alcohol causes drowsiness?

Amphetamines promote wakefulness by increasing the release of neurotransmitters like dopamine and norepinephrine in the brain, which enhances alertness and energy levels. In contrast, alcohol acts as a central nervous system depressant, enhancing the effects of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), leading to sedation and drowsiness. The contrasting effects of these substances are due to their differing mechanisms of action on neurotransmitter systems.