What is a common effect of caffeine intoxication?

Caffeine intoxication is characterized by a range of symptoms that result from the excessive consumption of caffeine. One of the hallmark effects is increased physiological arousal, which manifests as restlessness and an increased heart rate. Caffeine is a central nervous system stimulant that enhances alertness and can provoke a state of hyperactivity in individuals, leading to feelings of restlessness.

This stimulation occurs because caffeine blocks adenosine receptors in the brain, which normally promote sleep and relaxation. As a result, the individual may experience heightened energy levels, a faster heart rate, and an overall sense of being "wired." This aligns with the symptoms referenced in the correct answer, making it a key indicator of caffeine intoxication.

In contrast, options such as extreme fatigue and drowsiness, depression and lack of motivation, or unemotional and detached behavior do not correlate with the effects of caffeine, which tends to elevate energy and alertness rather than reduce these states.