Final answer:
Stimulants are the drugs that increase feelings of well-being, energy, and alertness, with possible side effects including depression after the initial effects wear off. They act by stimulating the brain and are exemplified by substances such as caffeine, nicotine, cocaine, and amphetamines.
Step-by-step explanation:
The group of drugs that can increase feelings of well-being, energy, and alertness while suppressing appetite but may be followed by depression are known as stimulants. These drugs stimulate the brain and nervous system, leading to increased arousal and wakefulness. Common examples of stimulants include caffeine, nicotine, cocaine, and amphetamines such as Adderall. While they can provide a euphoric high and feelings of intense elation and pleasure, the effect is often temporary, and when the drug wears off, users may experience a rebound effect resulting in depression. This is due to the way these drugs affect neurotransmitter levels in the brain, particularly dopamine.