Which of the following statements accurately describes hallucinogens?

Hallucinogens are substances that significantly alter perception, mood, and various cognitive processes, leading to changes in awareness and sensory input. This encompassing characteristic of hallucinogens includes experiences such as visual or auditory hallucinations, distorted sense of time, and an altered sense of self or reality. These effects are key indicators of how hallucinogens operate, making their ability to influence perception and create altered states of awareness their defining feature.

In contrast, the other statements do not accurately reflect the nature of hallucinogens. They are not used exclusively for treating depression, although some research is exploring their therapeutic potential in certain contexts; they primarily induce significant perceptual changes rather than merely suppress appetite or fatigue; they are not classified as stimulants, which instead typically increase energy and alertness. Thus, the statement that hallucinogens affect perception and lead to altered states of awareness is the one that accurately captures the essence of these substances.