Which of the following is an indicator of alcohol use?

Difficulty walking is a well-documented indicator of alcohol use, often referred to as ataxia. This impairment in coordination and balance results from alcohol's effect on the central nervous system. When consumed, alcohol can impair motor skills and cognitive functions, leading to unsteady gait and trouble maintaining balance. As a result, individuals under the influence may struggle to walk normally, which can be a key sign of intoxication.

In contrast, other indicators may relate to different substances or conditions. Profound euphoria can occur with various drugs, not specifically alcohol. Body overheating is more associated with stimulant use or environmental factors rather than alcohol. Needle marks are prominent signs of intravenous drug use, specifically associated with drugs like heroin or other opioids, rather than alcohol consumption. Thus, among the options presented, difficulty walking stands out as a clear and direct indicator of alcohol impairment.