How to Tell if Someone Is Drunk: A Clinician’s Guide to the Physical, Behavioural, and Cognitive Signs of Alcohol Intoxication, Stages of Drunkenness, and When Drinking Becomes a Medical Emergency

How to recognise alcohol intoxication in someone you know, the physical signs including slurred speech, unsteady walking, and bloodshot eyes, the behavioural signs of disinhibition, mood changes, and impaired judgement, how the signs change across the stages of drunkenness from mildly tipsy to severely intoxicated, when drunkenness becomes alcohol poisoning that needs emergency help, and what to do for a friend, family member, or partner who is drunk or showing signs of alcohol use disorder.

Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician and Addiction Medicine Specialist, Phuket Island Rehab.

You can usually tell if someone is drunk by a combination of physical, behavioural, and cognitive signs. The physical signs of alcohol intoxication include slurred speech, unsteady walking with stumbling or swaying, bloodshot or glassy eyes, flushed face, smell of alcohol on the breath or skin, dilated pupils, slowed reflexes, and clumsy movements. The behavioural signs include louder than usual speech, exaggerated emotions ranging from euphoria to anger to tearfulness, disinhibition with the person saying or doing things they would not normally do, mood swings, increased risk-taking, impaired judgement, and inappropriate social behaviour. The cognitive signs include difficulty concentrating, repeating themselves, forgetting recent conversations, confusion about time and place, slowed thinking, and reduced response to questions. The signs change with the level of intoxication: a mildly drunk person may show only mild flushing and increased talkativeness, a moderately drunk person shows slurred speech and unsteady walking, a severely drunk person may have difficulty staying awake, vomit, lose bladder or bowel control, and become unresponsive. Severe intoxication crosses into alcohol poisoning, which is a medical emergency requiring immediate help. Regular signs of drunkenness in someone close to you, particularly multiple times per week or at inappropriate times, can indicate alcohol use disorder and warrants professional assessment.

Why recognising the signs of drunkenness matters

The ability to tell if someone is drunk is a useful skill in many ordinary situations. Families want to know whether a relative driving home from a party is safe to drive. Parents want to know whether a teenager has been drinking. Partners want to understand changes in a spouse’s mood and behaviour at the end of the day. Hosts want to know when a guest has had enough. Friends want to know when to step in and look after someone whose drinking has crossed a line. Health workers, social workers, and clinicians need to recognise intoxication for clinical assessment. In all of these situations the question is the same: what does drunkenness look like, and how serious is it?

The signs of alcohol intoxication reflect alcohol’s effect on the central nervous system. Alcohol is a depressant that crosses the blood-brain barrier and reduces the activity of inhibitory and excitatory neurotransmitter systems. The behavioural disinhibition that drinkers experience in the early stages of intoxication reflects suppression of cortical control systems that ordinarily moderate impulse and emotion. The motor symptoms reflect alcohol’s effect on the cerebellum, which controls balance and coordination. The cognitive symptoms reflect impairment of attention, working memory, and executive function. The signs are reasonably predictable across people because alcohol acts on the same brain systems in everyone, although individuals vary in tolerance, body composition, and rate of metabolism.

Recognising drunkenness is also important because the signs can resemble or be confused with other conditions including head injury, stroke, hypoglycaemia, sedative or stimulant intoxication, medication side effects, and psychiatric illness. A confused, unsteady person with slurred speech is not always drunk, and assuming drunkenness can delay recognition of a medical emergency. Conversely a person who has been drinking heavily can mask the smell of alcohol with mints, gum, or strong perfume and present as something other than drunk, leading to under-recognition of intoxication in clinical and family settings. Knowing the full pattern of signs and considering alternative explanations is part of clinical and personal recognition.

The physical signs of being drunk

The most distinctive physical sign of alcohol intoxication is altered speech. Slurred speech, in which words are run together, consonants are softened, and the rhythm of speech is uneven, is one of the most reliable signs in moderately intoxicated people. In milder intoxication the speech may be louder than usual and more rapid, with the person interrupting others or speaking over the top of conversations. In more severe intoxication speech becomes mumbled and increasingly difficult to follow, with the person repeating themselves and losing track of the thread of conversation.

Movement and balance changes are another reliable sign. The person walks with an unsteady gait, sways while standing, has trouble maintaining a straight line, leans on walls or furniture for support, and may stumble or fall. Fine motor control is impaired, with the person dropping things, fumbling with keys or phones, and producing handwriting that is much worse than their normal. The classic field sobriety tests used by police are based on these motor signs and include walking heel-to-toe on a straight line, standing on one leg, and following a moving object with the eyes without moving the head. Untrained observers can apply the same principles informally.

The face often changes appearance during intoxication. The eyes typically become bloodshot or glassy, with the conjunctiva visibly red. The pupils may be dilated. The eyelids may droop. The face is often flushed, with reddening of the cheeks, nose, and forehead, particularly in lighter-skinned individuals and in people with the genetic alcohol flush response common in East Asian populations. The breath, the skin, and sometimes the clothing carry the distinctive smell of alcohol, which is stronger after spirits and beer than after wine. The smell can persist for hours after the person has stopped drinking and continues into the morning after.

The behavioural signs of being drunk

Behavioural changes are often more noticeable than physical signs to people who know the person well. The most consistent behavioural change is disinhibition. The person says things they would not normally say, takes risks they would not normally take, behaves more affectionately or more aggressively than usual, and acts on impulses that are usually controlled. The specific direction of the disinhibition depends on the person. Some people become louder, funnier, and more sociable. Some become emotional and tearful. Some become argumentative or aggressive. Some become flirtatious or sexually disinhibited. Some become sentimental and start saying things they have been holding back. The disinhibition is the common thread and is one of the most reliable behavioural markers.

Mood and emotional intensity change in characteristic ways. The intoxicated person experiences emotions more strongly and shifts between emotions more quickly. The same person may move from cheerful to angry to weepy within an hour without an obvious external trigger. The emotional shifts can be confusing for the people around them and can produce conflict that the intoxicated person will not remember the next day. The capacity to read social cues is impaired, with the person missing signals that others are uncomfortable, embarrassed, or angry. The person may persist in behaviours that others are trying to stop, including unwanted physical contact, repeated phone calls, or inappropriate jokes.

Judgement is impaired in ways that go beyond simple disinhibition. The intoxicated person typically underestimates risk and overestimates their own ability to handle dangerous situations. This includes driving, swimming, walking near roads or water, getting into physical altercations, accepting drinks from strangers, sending messages or emails they will regret, making financial decisions, and making sexual decisions. The combination of disinhibition and impaired judgement is the engine of many of the harms associated with drinking, including accidents, injuries, sexual harms, and decisions made in the heat of drinking that affect relationships and careers.

The cognitive signs of being drunk

Cognitive signs include difficulty concentrating on a conversation, asking the same question repeatedly because the person cannot remember the answer, forgetting recent events, confusion about time, place, or who is present, slowed responses to questions, and difficulty completing thoughts or sentences. The person may stare blankly, lose track of what they were saying mid-sentence, or appear to be operating in slow motion. Working memory is particularly affected, so the person cannot hold multiple pieces of information in mind at once. This is why drunk people are often poor at giving directions, following recipes, or doing arithmetic, all of which require working memory.

Memory for events during intoxication is often partial or absent. Alcoholic blackout, in which the person has no memory of a period during which they were awake and apparently functional, occurs at higher blood alcohol concentrations and is a sign of significant intoxication. Blackouts can be partial, with fragmentary memories, or complete, with no memory at all of a period of hours. The person in a blackout often appears to be functioning to those around them, but is laying down no memory for the events. Blackouts are an indicator of heavy drinking and are associated with increased risk of alcohol-related harms, including injuries and sexual assault.

Reaction time and decision speed are slowed by alcohol from low blood concentrations. The drunk person processes information more slowly than usual, takes longer to answer questions, and has slower physical reactions. The combination of slowed reaction time, impaired judgement, motor coordination problems, and disinhibition is why drink-driving is so dangerous and why drunk people are at increased risk of accidents in many other domains. The slowing is not always obvious to the drunk person, who may believe they are functioning normally because the same slowing affects their assessment of their own functioning.

The stages of being drunk and what blood alcohol concentration looks like

The signs of being drunk change as blood alcohol concentration rises. At low concentrations, around 0.02 to 0.04 percent, most people experience mild relaxation and lowered inhibitions but show few outward signs. The face may be slightly flushed and the person may seem a little more talkative. This is the after-one-drink stage and most people are not impaired enough that observers can confidently say they are drinking. At 0.05 to 0.08 percent, the legal driving limit in many countries, the signs become more visible. The person is noticeably more relaxed, talks more, may slur slightly, has measurably slower reaction times, and shows reduced inhibitions. Most adults at 0.08 percent are clearly affected by alcohol to observers who know them.

At 0.08 to 0.15 percent the signs become unmistakable. Slurred speech is obvious. Walking is unsteady. Judgement is significantly impaired. Mood becomes labile. The person may begin to lose track of where they are in a conversation. At 0.15 to 0.25 percent the person is severely intoxicated. Speech is slurred to the point of being difficult to understand. Walking requires support. Vomiting may occur. The person may become aggressive or tearful or both. Blackout becomes likely. Risk of accidents and injuries is high. At 0.25 to 0.35 percent the person is in danger. They may lose consciousness, cannot stand, may vomit while semiconscious with risk of aspiration, and may have respiratory depression. Above 0.35 percent the risk of death from respiratory depression or aspiration is significant, and emergency medical care is needed.

These ranges describe what blood alcohol concentration corresponds to which level of impairment for most adults, but tolerance varies. Heavy drinkers develop functional tolerance and may show fewer outward signs at concentrations that would severely impair a non-drinker. This functional tolerance does not protect against the underlying organ effects of alcohol or against alcohol poisoning at high concentrations, but it can mask the signs of drunkenness. People who do not drink often, or who are taking sedating medications, can show signs of significant impairment at lower blood concentrations than would impair a regular drinker.

Alcohol poisoning: when drunk becomes a medical emergency

Alcohol poisoning is a medical emergency that occurs when blood alcohol concentration rises to a level that suppresses brain function, respiratory drive, and protective reflexes. The signs of alcohol poisoning include confusion or unresponsiveness, vomiting, seizures, slow or irregular breathing of fewer than 8 breaths per minute or with gaps of 10 seconds or more between breaths, pale or bluish skin, low body temperature, and unconsciousness from which the person cannot be roused. A person showing any of these signs needs emergency medical help and should not be left to sleep it off.

Many of the deaths from alcohol poisoning happen because friends or family did not recognise the severity of the intoxication and assumed the person would be fine after sleeping. Alcohol absorption continues for some time after the last drink, so the blood alcohol concentration of someone who has stopped drinking can still rise. A person who looks deeply asleep but actually has a blood alcohol concentration above 0.35 percent can stop breathing or vomit and aspirate while unconscious. The decision to seek medical help in any doubt is almost always the right one. Emergency departments routinely manage alcohol intoxication and do not contact the police or college authorities in most jurisdictions.

Combining alcohol with other depressants including opioids, benzodiazepines such as Xanax or Valium, sleep medications such as Ambien, or illicit drugs such as heroin or fentanyl substantially increases the risk of respiratory depression and death. The deaths from accidental overdose often involve a combination of alcohol with another depressant rather than alcohol alone, even when the alcohol concentration was not at the level usually associated with fatal poisoning. Any person who has been drinking and may have also taken other depressants needs particularly careful observation.

How to tell if someone is drunk versus on other substances

Distinguishing alcohol intoxication from intoxication with other substances can be useful in some situations. The smell of alcohol on the breath, when present, is highly suggestive of drinking, though it is not always present and the absence of the smell does not rule out drinking. Slurred speech, unsteady walking, and disinhibition are characteristic of alcohol but also of sedative medications and of cannabis at high doses. Stimulant intoxication produces a different picture, with rapid speech, dilated pupils, sweating, agitation, and elevated heart rate, rather than the slowed picture of alcohol. Opioid intoxication produces pinpoint pupils, drowsiness, slow speech, and slow breathing without the prominent disinhibition of alcohol.

Cannabis intoxication can produce slowed thinking, red eyes, increased appetite, and giggling, with less prominent motor incoordination than alcohol unless very large doses have been used. MDMA and other entactogenic stimulants produce sweating, jaw clenching, dilated pupils, elevated mood, and feelings of closeness to others, which is a distinctive picture. Hallucinogens produce altered perception and abnormal sensory experiences that the person may describe. Many real situations involve mixed intoxication with alcohol plus one or more other substances, and the combined picture can be confusing. When in doubt, the safest approach is to assume the situation could be serious and to seek help.

Some medical conditions can resemble intoxication. Hypoglycaemia in someone with diabetes produces confusion, unsteadiness, sweating, and altered behaviour that can look like drunkenness. Stroke can produce slurred speech, weakness, and confusion. Head injury can produce confusion, vomiting, and unsteadiness. A first seizure can produce a postictal state of confusion and slow responsiveness. Patients who seem drunk but who do not have the smell of alcohol, who have not been observed drinking, who are old or have known medical conditions, or who deteriorate when they should be sobering up, should be evaluated medically rather than assumed to be drunk.

What to do when a friend or family member is drunk

For mild to moderate drunkenness the priorities are safety and not making things worse. The drunk person should not drive, ride a bike, swim, or operate machinery. Take car keys away if needed. Arrange a taxi, a ride home from a sober friend, or a place for them to stay safely. Keep them away from situations where their impaired judgement could cause harm. If they are arguing or trying to send messages they will regret, gently delay or redirect rather than confronting. The drunk person will not remember reasoned arguments and will often escalate if confronted directly.

For more severe drunkenness the priorities are safety, prevention of aspiration, and watching for signs of poisoning. Stay with the person. If they need to lie down, put them on their side rather than on their back, to reduce the risk that vomit will be inhaled into the lungs if they are sick. Watch their breathing and check that they are responsive. Do not leave them alone to sleep it off. Do not give them coffee or food in an attempt to sober them up. Do not put them in a cold shower. Time is the only thing that lowers blood alcohol concentration and at best you are looking after them until they sober up enough to be safe.

For severe drunkenness or any sign of alcohol poisoning, call emergency services. The criteria for emergency help include unresponsiveness, slow or irregular breathing, blue or pale skin, vomiting while unconscious, seizures, and any combination of these. The fear of getting the drunk person in trouble is rarely a good reason not to call. Good Samaritan laws in many jurisdictions protect callers seeking help for a person experiencing alcohol poisoning. The risk of not calling, including death from aspiration or respiratory depression, is much greater than the risk of any consequence of calling.

When the signs become a pattern: recognising alcohol use disorder

Occasional drunkenness in someone you know is one situation. Regular drunkenness, drunkenness at inappropriate times of day, drunkenness that affects work or family responsibilities, and drunkenness that the person cannot reduce despite obvious harms are different situations and indicate that alcohol use has crossed into alcohol use disorder. Signs that warrant concern include drinking before work or during the working day, drinking alone regularly, drinking that produces blackouts, drinking that produces accidents or injuries, drinking that causes the person to miss commitments, drinking that affects parenting, hidden drinking, lying about how much has been drunk, and drinking that the person says they will reduce but cannot.

The DSM-5 criteria for alcohol use disorder require two or more of eleven specific patterns over the past twelve months including drinking more or longer than intended, unsuccessful efforts to cut down, time spent obtaining or using alcohol or recovering from its effects, craving, failure to fulfil major obligations, continued use despite social problems, important activities given up, recurrent use in physically hazardous situations, continued use despite physical or psychological harm, tolerance, and withdrawal. Two or three criteria define mild alcohol use disorder, four or five moderate, and six or more severe. Many people who would meet these criteria do not see themselves as alcoholic because they are still functioning, but the diagnosis is clinically meaningful and effective treatments are available.

Approaching someone you suspect has alcohol use disorder is difficult and often produces defensiveness. The best approach is usually to wait until the person is sober, to express concern about specific behaviours rather than to label the person as an alcoholic, to focus on the impact of the drinking on people who love them rather than on the drinking itself, and to be ready with information about treatment options if the person is open to discussion. Confrontational interventions can work but are often counterproductive and benefit from professional support. Many families benefit from talking with an addiction counsellor before approaching the person who is drinking, both to plan the conversation and to address the family’s own response to the situation.

Frequently asked questions

How can you tell if someone has been drinking but is hiding it?

Hidden drinking is often signalled by the same physical and behavioural changes as visible drinking, with the smell of alcohol sometimes covered by mints, gum, perfume, or coffee. Other clues include unexplained mood changes in the evening, decreasing engagement with the family, lateness or absence from commitments, missing money, hidden bottles around the house, increased privacy, and changes in eating, sleeping, and personal care. People who drink secretly often drink during specific routines: in the car, in the garage, in the bathroom, after the family has gone to bed.

How drunk is too drunk?

Any level of drinking that produces slurred speech, unsteady walking, impaired judgement, or behaviour the person would not normally engage in is enough drinking to affect their safety and the safety of others. Any drinking that puts a person behind the wheel of a car or near water is too much. Any drinking that produces a blackout is well past the safe range. Severe intoxication that crosses into the symptoms of alcohol poisoning is a medical emergency.

How long do the signs of being drunk last?

Blood alcohol concentration falls by about 0.015 percent per hour for most adults, so someone with a blood concentration of 0.15 percent will take approximately 10 hours to return to zero. The visible signs of intoxication usually correspond to blood concentration. A person who has been heavily drinking can show signs of intoxication for many hours after their last drink, and the after-effects including fatigue, headache, nausea, and impaired concentration of the hangover can last another 12 to 24 hours.

Can you tell if someone is drunk just from their eyes?

Eye changes are often visible but are not always diagnostic on their own. Bloodshot or glassy eyes, dilated pupils, and droopy eyelids are common in intoxication but can also be produced by tiredness, allergies, cannabis use, and several medical conditions. The combination of eye changes with slurred speech, unsteady gait, behavioural changes, and the smell of alcohol is much more reliable than eye changes alone.

What is the difference between tipsy and drunk?

Tipsy is an informal term for mild intoxication, usually at blood alcohol concentrations below 0.06 percent, with mild relaxation, slight flushing, and lowered inhibitions but no significant impairment of speech or walking. Drunk usually refers to clear intoxication at 0.08 percent and above, with visible signs of impairment. The boundary is not sharp and the terms are used informally in different ways by different people.

Should I let my drunk friend sleep it off?

Mildly drunk people can sleep off the alcohol safely. Moderately drunk people should be checked on regularly through the night to make sure they are still responsive and breathing normally. Severely drunk people should not be left alone and should be evaluated for alcohol poisoning. If you are unsure about how drunk a person is, the safer action is to stay with them, position them on their side, and contact emergency services if any signs of alcohol poisoning appear.

Summary

Telling if someone is drunk involves recognising a combination of physical, behavioural, and cognitive signs. The physical signs include slurred speech, unsteady walking, bloodshot or glassy eyes, flushed face, smell of alcohol, slowed reflexes, and clumsy movements. The behavioural signs include disinhibition, mood swings, impaired judgement, and inappropriate behaviour. The cognitive signs include difficulty concentrating, repeating themselves, memory problems, and slowed responses. The signs intensify as blood alcohol concentration rises, from mild relaxation at low concentrations through obvious impairment to severe intoxication and ultimately alcohol poisoning, which is a medical emergency. When recognising drunkenness in someone close to you, the priorities are safety, prevention of injury, watching for signs of poisoning, and avoiding situations where impaired judgement could produce lasting harm. Regular signs of drunkenness, particularly at inappropriate times or to the point of harm, suggest alcohol use disorder and warrant professional assessment. Effective treatment for alcohol use disorder is available and most people who engage in treatment experience meaningful improvement. As Dr. Ponlawat Pitsuwan summarises, “The signs of drunkenness are familiar to anyone who has lived with a heavy drinker, and the question for family members is rarely how to recognise the signs but what to do about a pattern that has become harmful. The answer is almost never solved by the family alone. Professional help, started gently and offered repeatedly, is the path that most often works.”

Sources

• National Institute on Alcohol Abuse and Alcoholism. Understanding the dangers of alcohol overdose. https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/understanding-dangers-alcohol-overdose
• Centers for Disease Control and Prevention. Alcohol poisoning deaths. https://www.cdc.gov/alcohol/fact-sheets/alcohol-poisoning-deaths.html
• American Psychiatric Association. DSM-5 criteria for alcohol use disorder. https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/alcohol-use-disorder-comparison-between-dsm
• World Health Organization. Global status report on alcohol and health 2018. https://www.who.int/publications/i/item/9789241565639
• National Health Service. Alcohol misuse. https://www.nhs.uk/conditions/alcohol-misuse/
• Substance Abuse and Mental Health Services Administration (SAMHSA). National Helpline. https://www.samhsa.gov/find-help/national-helpline
• Australian Department of Health. Australian guidelines to reduce health risks from drinking alcohol. https://www.nhmrc.gov.au/about-us/publications/australian-guidelines-reduce-health-risks-drinking-alcohol

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