What is one common effect of hallucinogens on an individual?

Hallucinogens are substances that significantly alter an individual's perception, mood, and cognitive processes. One of the hallmark effects of these drugs is the alteration of reality, which can manifest in various ways such as visual distortions, changes in sensory perception, and an altered sense of time and space. This altered perception can lead to experiences that feel profoundly real to the individual, even though they may not correspond to the actual environment. While increased heart rate, decreased appetite, and enhanced concentration can be associated with some substances, they are not defining characteristics of hallucinogens. Instead, the key aspect that distinguishes hallucinogens is their ability to fundamentally change the way people perceive and interpret the world around them.