How to Tell If Someone Is High. If you are not accustomed to being around people who use drugs, you may not know how to spot drug abuse or be able to tell when someone is high. You should know the signs and symptoms displayed by drug abusers for your own safety and security. Read on to learn to recognize when someone is in an altered state.

Watch for unexplained behavior changes. A normally sociable person may not want to talk all of a sudden. Conversely, question the motives of a shy person who suddenly becomes overly gregarious. Expect a denial if you confront someone on drugs.

Notice sudden escalations in the person's speaking voice. People on drugs often misjudge how loud or low quietly they are talking. They will either stand too close as well, or constantly move away, avoiding eye contact.

Check out someone who laughs or giggles uncontrollably, especially if the laughter is misplaced or inappropriate. Watch when two or more people seem to share a secret and whisper and laugh about it in front of others. People on drugs also are notorious for forgetting things that were just said, or that happened moments ago.

Sniff for any strong scents, either sweet smelling or otherwise, on their breath or body. Some drugs, like marijuana, produce a strong scent. Sometimes a drug user may put on excessive amounts of cologne or perfume to mask drug odors. Other times, a person may smell bad if he has forgotten to shower while in a daze.

Look into the eyes of someone you suspect of drug abuse. Dilated eyes in a lighted room, or pinpoint pupils in the dark are indicators of drug use. Check also for bloodshot eyes. Pay attention to the way a person walks too. Stumbling and dizziness, while often signs of drunkenness, may also be a sign of drug use.