How to Tell if Someone Is High: Recognizing Signs of Drug Intoxication

It is essential to understand that you CAN’T tell, for certain, if someone is “high.” You may see physical signs which are consistent with drug use, or notice behaviors that are different from an individual’s characteristic behaviors, or suspect illicit use of drugs, but you can’t tell for certain without their admission of drug use or a drug test. 

Keep in mind that there are numerous physical and mental medical conditions that can be mistaken for the illicit use of drugs. Some of these include migraine headaches, stroke, and other neurological conditions. Depression, anxiety, psychosis, schizophrenia, and other mental health disorders may cause abnormal physical signs and uncharacteristic behaviors. Head trauma could be a problem. 

Metabolic disorders can show signs and symptoms characteristic of drug use. The most immediately threatening situations are associated with diabetes, such as very high blood sugar or diabetic coma, or an insulin reaction, often with dangerously low blood sugar. These situations call for emergency medical attention. Medication reactions can also mimic illicit use of drugs.

It is never useful to engage in heated arguments or accusations with someone showing signs and symptoms of illicit or inappropriate use of drugs, or a condition which can appear similar. These situations call for medical evaluation. If your suspicion for illicit drug use is great, remember that you can’t engage in rational dialogue with someone whose thinking is irrational. You also want to avoid triggering behaviors that may escalate to harm you or the person of concern.

The process of identifying the influence of drug use in people you know can become extremely difficult to handle. Your ability to recognize warning signs allows you to give appropriate help and support, which might result in saving someone’s life.

Quick Answer

Being “high” refers to having an altered state of consciousness caused by psychoactive substances that change brain chemistry, leading to symptoms like euphoria, sedation, or hallucinations. These substances act on neurotransmitters, the chemicals in the brain that regulate mood, perception, movement, and judgment, and can have numerous effects, detailed below.

Common signs that someone might be high include:

Physical indicators like bloodshot eyes, unusual pupil size (dilated or constricted), slurred speech [1], poor coordination, flushed or pale skin, and sweating. You might also notice unusual odors on their breath or clothing.

Behavioral changes often include sudden mood swings, euphoria, paranoia, secretive behavior, impaired judgment, or unusual energy levels.

Signs vary significantly depending on the substance used, the person’s tolerance, and individual factors. Observing a combination of symptoms provides more meaningful insight than any single sign alone.

How Drugs Affect the Body & Brain

Understanding how substances work helps explain why different drugs produce varied effects. Drugs interact with your brain’s chemical messengers (neurotransmitters) that regulate mood, energy, pain perception, thinking, and motor control.

Different drug categories affect the brain distinctly:

Depressants (alcohol, benzodiazepines) slow the central nervous system by enhancing GABA, creating relaxation but impairing coordination. Stimulants (cocaine, methamphetamine) increase dopamine and norepinephrine, creating heightened alertness and energy. Opioids (heroin, fentanyl) bind to opioid receptors, blocking pain but depressing breathing. Hallucinogens (LSD, psilocybin) disrupt serotonin signaling, altering perception and thought. Cannabinoids (marijuana) activate cannabinoid receptors, affecting memory, coordination, and appetite.

Why Signs Differ

Visible signs differ because substances affect different neurotransmitter systems. Stimulants cause dilated pupils and rapid speech, while opioids cause constricted pupils and drowsiness. Individual responses vary based on body weight, metabolism, tolerance, mental health,  whether other substances are present, and other factors

Common Signs That Someone Is High

Learning to recognize drug intoxication signs requires understanding both general indicators and substance-specific symptoms.

Physical Signs

The human body shows drug consumption through physical signs which include bloodshot eyes and dilated or constricted pupils, skin color changes and sweating problems, unsteady walking and speech difficulties, jaw stiffness and unusual breath and clothing smells. The use of depressants leads to dangerous breathing pattern slowdowns but stimulants cause breathing rates to increase rapidly.

Behavioral Signs

High symptoms include dramatic mood swings, euphoria or extreme relaxation, paranoia or anxiety, impaired judgment, secretive behavior, and loss of coordination. Energy levels shift dramatically—stimulants create restlessness while depressants cause lethargy.

Psychological Signs

Some substances produce profound changes: hallucinations, confusion, memory lapses, or disorganized thinking, particularly with hallucinogens or high-potency THC products.

Substance-Specific Signs of Being High

Understanding what a high person may look like when using specific substances provides more accurate recognition.

Marijuana and THC Products

Bloodshot eyes, droopy eyelids, slowed reaction time, increased appetite (“the munchies”), dry mouth, and strong herbaceous odor [2]. Mood may shift from relaxed to anxious or paranoid, especially with high-potency products. Effects typically last 2-3 hours when smoked, 4-10 hours with edibles [3].

Alcohol

Flushed face, slurred speech, impaired coordination, unsteady walk [1], exaggerated emotions, lowered inhibitions, possible vomiting. Severe intoxication includes confusion, vomiting, seizures, slow breathing, and unconsciousness.

Stimulants (Cocaine, Methamphetamine, Prescription ADHD Medications)

Dilated pupils, rapid speech, heightened energy, restlessness, increased heart rate and temperature, reduced appetite, jaw clenching or teeth grinding. Aftereffects include irritability, depression, or “crashing.”

Opioids (Heroin, Fentanyl, Oxycodone)

Constricted (“pinpoint”) pupils, drowsiness (“nodding off”), slowed breathing, itching or scratching, slowed reaction time. Overdose signs require immediate 911 calls: blue lips, unresponsiveness, very slow or stopped breathing. Give naloxone (Narcan) if available.

Depressants and Benzodiazepines (Xanax, Valium)

Drowsiness, slurred speech, poor coordination, confusion, dizziness, sometimes aggression. Combining with alcohol or opioids creates life-threatening risks [2], such as suppressing breathing.

Hallucinogens (LSD, Psilocybin, Ketamine)

Dilated pupils, distorted perception of time and reality, visual or auditory hallucinations, rapid mood changes. Physical signs include nausea, tremors, or sweating [4].

Inhalants

Chemical odor on breath or clothing, paint or stains on skin, runny nose, slurred speech, dizziness, nausea, headaches.

Physical vs. Behavioral Signs: Why They Differ

Physical signs result from the drug’s direct interaction with the nervous system—changes in pupils, heart rate, breathing, and coordination. Behavioral signs reflect changes in mood, energy, and thinking, depending on environment, personality, tolerance,  mental health, and other factors.

Poly-Substance Use

Combining substances (like alcohol and Xanax) can mask or exaggerate signs, making detection more challenging and dramatically increasing overdose risk.

What to Do If You Suspect Someone Is High

Assess Immediate Risk

If someone shows these signs, call 911 immediately: difficulty breathing, unresponsiveness, blue lips or skin, seizures, extreme confusion, choking sounds, or loss of consciousness. Good Samaritan laws protect people who call for help during emergencies.

Ensure Safety

Remove car keys and prevent driving. Clear dangerous objects. Move them to a calm, quiet space. If sedated, position them on their side to prevent choking. Never leave a heavily intoxicated person alone. 

Ensure your own safety if someone is aggressive, violent or threatens violence, or is in possession of weapons. Do not attempt to subdue a violent person. Keep your distance or leave the area. Call 911 for help.

Approach with Compassion

Keep your voice calm. Use simple statements: “I’m concerned about you. Let’s sit down. I’m staying with you.” Avoid shaming language or accusations. Don’t argue with hallucinations or paranoia. Save serious conversations for when they’re sober.

Stay with Them If Safe

Monitor for worsening symptoms. Keep them awake if they’ve used depressants. Track time and symptoms for medical personnel. Be prepared to provide information about substances used.

Plan Next Steps

Once sober, express concern from caring, not judgment. Use “I” statements: “I felt scared. I care about you and I’m worried.” Listen more than you speak. Offer specific help: “I’ve found counseling services. Can we look at them together?” You can call a healthcare provider or treatment center to get guidance about talking to the person of concern.

When & Where to Seek Professional Help

Acute Situations

Seek immediate medical attention for suspected overdose, severe hallucinations or psychosis, suicidal thoughts, chest pain, difficulty breathing, seizures, or injuries sustained while intoxicated. Seek immediate help for violence or potential violence.

Chronic Concerns

Repeated intoxication indicates patterns requiring intervention. If substance use interferes with responsibilities, if the person can’t stop on their own, physical or mental health deteriorates, relationships suffer, or if withdrawal symptoms appear, professional treatment is necessary. Co-occurring mental health conditions require integrated treatment.

Resources & Hotlines

Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline: 1-800-662-HELP (4357) provides free, confidential treatment referrals 24/7.

Crisis Text Line: Text HOME to 741741 for immediate support.

988 Suicide & Crisis Lifeline: Call or text 988 for mental health or substance use crises.

At Aura Recovery, we provide compassionate care including detox, short-term inpatient treatment, medication-assisted treatment, and intensive outpatient programs tailored to individual needs.

Prevention & Education: Building Awareness

Family & Peer Education

Learn about common substances and their effects. Talk with children about drugs using factual information. Discuss prescription medication safety. Foster open communication without judgment. Model healthy coping mechanisms. Parents have powerful influence over helping their kids avoid drugs.

Healthy Coping Strategies

Mental health support through therapy provides tools for managing conditions that drive substance use. Physical activity, mindfulness practices, support groups, and alternative pain management reduce reliance on substances.

Advocacy and Community

Support harm reduction programs like naloxone (Narcan) distribution. Advocate for expanded treatment access. Combat stigma through language and education. Support recovery-friendly workplace policies and housing initiatives.

Conclusion & Call to Action

Learning how to tell if someone may be high empowers you to respond effectively. Remember that recognizing signs of being high requires looking at complete patterns rather than isolated behaviors. Physical indicators combine with behavioral shifts to create recognizable patterns. Understanding what a high person looks like varies tremendously by substance, and approaching with compassion creates the safest environment for both crisis management and recovery conversations. Remember, a physical or mental medical condition not related to substance use may be the problem.

You don’t have to navigate these concerns alone. At Aura Recovery in Scottsville, Kentucky, our warm, knowledgeable team understands addiction’s complexity and the courage it takes to seek help. We offer comprehensive services, including medical detox (using medication and other interventions under the guidance of a medical professional to safely withdraw from a substance), short-term inpatient treatment, medication-assisted treatment, and intensive outpatient programs designed to support lasting recovery.

If you’re concerned about someone’s substance use, or if you’re struggling yourself, we invite you to reach out. Our confidential, compassionate team is here to answer questions and discuss treatment options tailored to your unique situation. Recovery is possible, and it starts with a single step. Contact Aura Recovery today to begin the journey toward health, healing, and hope.

Frequently Asked Questions