Which behavioral sign might indicate the use of hallucinogens?

The behavioral sign that might indicate the use of hallucinogens is the presence of hallucinations or delusions. Hallucinogens, such as LSD or psilocybin mushrooms, are substances that can significantly alter an individual's perception of reality. Users may experience visual or auditory hallucinations, leading to distorted interpretations of their environment. Delusions, which are fixed false beliefs, may also occur under the influence of these substances, causing individuals to perceive situations in ways that are disconnected from reality.

While other options like increased productivity or improved memory recall might suggest enhanced cognitive function, these effects are not typically associated with hallucinogen use. Users often report decreased coordination and impaired cognitive abilities instead of improvement. Therefore, hallucinations or delusions are the hallmark behaviors that distinctly indicate hallucinogen use.