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How Can You Tell if Someone Is High on Drugs?


The average person that’s unfamiliar with drug use doesn’t usually know how to tell if someone is high. Still, drug use has become a pervasive part of everyday life and over the last 2 decades prescription drugs have brought drug use into more homes and businesses than ever before.

According to the National Survey on Drug Use and Health 38% of adults battled a substance abuse disorder. Drug users are becoming more sophisticated at concealing their behavior. To help parents, law enforcement, employers and friends Drug Test City has put together a definitive guide on how to tell if someone is high.

Physical Signs That May Indicate Someone is High

The body gives away its secrets if you listen. When proactively identifying drug or alcohol impairment I like to start at the top of the head and work my way down.

Drug Impairment Indicators of the Eyes

The preferred field sobriety test of Law Enforcement is the Horizontal Gaze Nystagmus Eye Test because the eyes are the most obvious physical indication of impairment and it’s the only indicator associated with the eyes that will hold weight in court.

how to tell if someone is high

The test for eye nystagmus is a complex and lengthy test that checks for involuntary jerking when the eye moves to a certain angle, but this is useless for the average person trying to covertly make a determination. Parents and other authority figures however may be able to perform sobriety testing or even a drug test to get more definitive answers. Other indicators are more obvious, non intrusive and easily noticed.

  • Redness
  • Glassiness
  • Constricted or dilated pupils
  • Involuntary or rapid eye movement
  •  Avoiding eye contact
  • Watery or dry eyes
  • Excessive blinking
  •  Tired eyes

Examples of Eye Indicators

Olfactory Drug Impairment Indicators

Depending on the route of administration drug use can case runny nose, redness, bloody nose and dry sinuses.

Users that snort drugs have a hard time concealing the drug residue that can become caked in their nostrils or lightly color one nostril’s hairs.

The most obvious olfactory indicator that someone is high or recently used drugs is your nose, not theirs. Alcohol and marijuana both have a pungent odor that is hard to mask. The majority of traffic citations issued for marijuana use cite the smell as probable cause. Careful users will carry cologne or perfume in their car and try to conceal the smell. If someone smells like fresh perfume after every break and coming back from lunch I would have strong suspicions of drug use. These smells will be easier to notice when the user is moving around or speaking.

Drug Impairment Indicators of the Mouth

The mouth may be the most affected part of the body by drug use. Bad oral hygiene can indicate long term drug use, but several other symptoms an suggest that a person is currently under the influence.

Dry mouth: Several classes of drugs dehydrate the body and cause dry mouth. Everything from marijuana to methamphetamine can lead to dry mouth.

Lip smacking and Licking Lips: This is a common reaction to dry mouth.

Teeth clenching: Many stimulants will cause users to clench their teeth.

Bad breath: Users that are high functioning on a maintenance drug such as Methadone or Suboxone may do a good job at hiding outward signs and symptoms of their drug use, but they will still usually suffer from dry mouth which causes bad breath over time.

Pot / Alcohol breath: Less careful users will often emit the smell of their preferred drug when they speak. More careful users may try and cover it up with excessive mouthwash.

Excessive talking: Most stimulants and many narcotic pain relievers cause euphoria and excessive talking. If someone has excessive bouts of talkativeness it’s very likely to influence of drugs.

Appetite: Drug use most often decreases appetite, although it can also increase it. Some drugs like Methadone cause users to crave sweets. A change in appetite coupled with other signs can be a strong indicator.

Slurred or rushed speech: Most drugs will have an effect on the user’s speech. Be aware of anything that is unusual in speech pattern or dialect.

Other Physical Signs of Drug Impairment

  • Exhaustion: Either from drug use or an associated lack of sleep. Fatigue can manifest itself physically in several different ways .
  • Track marks: IV drug users sometimes leave visible signs on their arms and hands. Others will noticeably attempt to hide their arms from plain view. It isn’t normal for someone to wear a jacket on hot summer days, wear a wrist band around their elbow or have makeup on their arm.
  •  Burns on hands and lips: Crack and meth users handle hot pipes and often burn their hands and lips.
  •  Sores: Using drugs itself rarely causes sores, but instead addicts will scratch and pick at their faces and arms.

Behavioral Signs Used to Tell When Someone is High

A person’s behavior can reveal a lot about themselves, especially any recent drug use. While it’s easy to notice exaggerated movements of a methamphetamine addict or a heroin junkie in a nod, subtle clues are harder to notice but just as hard to conceal. Reading someone’s behavior to suggest drug use is just another form of deception detection.

Movement: Stimulants can cause users to move erratically and spastically. Other drugs like marijuana can slow reaction time and delay movements.

The video below shows a woman high on flakka outside an apartment complex. This type of behavior isn’t common, but less exaggerated movements are common in most stimulant users.


Speech: Slurred speech is the hallmark of many narcotics and alcohol. Prescription pills like benzodiazepines and stronger narcotic pain relievers can cause slurred speech. As I mentioned before stimulants and opiates can cause euphoria and talkativeness. One of the most common indicators in a high functioning drug user, look for a person to have an episode of higher energy at specific times of day.

Energy level: Drug use is like a roller coaster of motivation and energy. Although some mental health diagnoses mimic this pattern, consider the subject’s indicators as a whole.

Confidence: A euphoric high will increase a person’s confidence. Specifically look for major shifts that are recurring.

Mood Swings: Newer users especially are affected by mood swings. Anger is the most common, but withdrawal from many drugs causes uncontrollable depression during the onset. The euphoria that accompanies a high is just as quickly replaced by lethargy later in the day.

Memory: Many drugs are associated with forgetfulness. Short term memory loss has long been noted as a side effect of marijuana use. Benzodiazepines such as Xanax can cause even more severe memory loss. Almost all drugs will cause some level of loss of focus. In the corporate world and college smart drugs have become popular, which have the opposite effect. Adderall can help students study for an exam, but it’s important to remember that it’s an amphetamine and is just as dangerous and addictive as a street drug.

Subtle Cues of Intoxication

Most of the time heavy drug users and those that exhibit obvious symptoms are easily spotted. You’re going to use this guide to identify the not-so-obvious ones.

Drug addicts need to work and live life too. They’ve been hiding their drug use for a long time and learning to work around people noticing. An advantage to being high everyday is that people recognize your behavior as normal.

If you have reasonable suspicion that an employee, child or subordinate is impaired you should drug test them immediately. If it’s a colleague or superior, you will want to verify your suspicions as much as possible before reporting them or making an accusation. People in higher positions are more likely to be higher functioning.

You will need to pay closer attention to observe mild symptoms and associate unrelated symptoms with each other. The biggest thing is unusual behaviors or fluctuating moods. Since many of the milder signs are common in the general population you should track observation of symptoms and look for patterns. Consider giving others the benefit of doubt though; it’s just as easy for them to make accusations and find an aspect of your life or work to draw attention to.

If someone that is actively concealing drug or alcohol use suspects you have noticed they may become nervous. Watch for signs like:

  • Avoiding eye contact
  • Shaking
  • Elevated heart rate

We hope this list helps you identify intoxication when it is a danger to you or those around you. Always use a drug test to confirm suspicions before issuing punishments or taking administrative actions against someone. We should all try and be more compassionate toward those with substance abuse issues, feel free to contact the staff at Drug Test City if you would like guidance on dealing with a friend, family member or co-worker that you believe has a substance abuse problem.