What is a notable effect of hallucinogen abuse?

Flashbacks are a significant effect of hallucinogen abuse. This phenomenon, often referred to as hallucinogen persisting perception disorder (HPPD), occurs when an individual experiences sudden and unexpected recurrences of the perceptual distortions that occurred during a prior hallucinogenic experience. These flashbacks can happen even when the individual is no longer under the influence of the drug, and can be triggered by stress, fatigue, or drug use. Flashbacks can be disorienting and distressing, and they highlight the long-lasting impact that hallucinogens can have on the brain's processing of sensory information.

In contrast, other options provided do not accurately represent the effects associated with hallucinogen use. Increased physical strength, heightened sense of reality, and improved motor skills are not effects typically linked to hallucinogens. Instead, users may experience altered perceptions of reality, emotional shifts, and impaired motor coordination, rather than enhancements in physical capabilities or skills.