An alcoholic is someone whose drinking has become compulsive and harmful, continuing despite negative consequences to their health, relationships, or daily life. The medical community now uses the term “alcohol use disorder” (AUD) instead, which exists on a spectrum from mild to severe. But the core idea remains the same: when a person has lost reliable control over how much or how often they drink, and their life is worse because of it, that pattern fits the definition.
How Doctors Define It
The standard medical definition comes from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which lists 11 possible symptoms. Having two or more within a 12-month period qualifies as alcohol use disorder. The number of symptoms determines severity: 2 to 3 is mild, 4 to 5 is moderate, and 6 or more is severe. That severe category is closest to what most people mean when they say “alcoholic.”
The 11 symptoms cover three broad areas. Some relate to loss of control: drinking more than you intended, wanting to cut down but being unable to, spending a large amount of time drinking or recovering from it, and experiencing strong cravings. Others involve life consequences: failing to meet responsibilities at work, home, or school, continuing to drink even when it causes relationship problems, giving up activities you used to enjoy, and drinking in situations where it’s physically dangerous. The final group involves your body’s adaptation: developing tolerance (needing more alcohol to feel the same effect) and experiencing withdrawal symptoms like shakiness, sweating, nausea, a racing heart, or trouble sleeping when the effects wear off.
You don’t need to check every box. Someone who repeatedly drinks more than they planned, has tried and failed to cut back, and has given up hobbies because of drinking meets the threshold, even if they’ve never had a withdrawal seizure.
What Counts as Heavy Drinking
Not everyone who drinks heavily qualifies as having AUD, but heavy drinking is the clearest risk factor. The CDC defines binge drinking as four or more drinks on a single occasion for women, or five or more for men. Heavy drinking means eight or more drinks per week for women, or 15 or more per week for men. These thresholds aren’t arbitrary. They mark the point where the risk of developing dependence, liver disease, and other complications rises sharply.
A “standard drink” is smaller than many people realize: 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. A large glass of wine at a restaurant is often closer to two drinks. A strong craft beer can count as one and a half or two. Many people who consider themselves moderate drinkers are actually drinking at heavy levels once you measure accurately.
Why It Happens: Genetics and Environment
Research on twins estimates that 48 to 58 percent of the risk for developing alcohol dependence comes from genetics. The remaining risk comes from individual environmental factors: trauma, stress, peer influence, early exposure to alcohol, and mental health conditions like anxiety or depression. Having a parent with AUD roughly doubles your risk, but it doesn’t make dependence inevitable. Plenty of people with strong family histories never develop a problem, and plenty of people with no family history do.
What genetics actually influences is how your brain responds to alcohol. Some people experience a stronger reward signal from drinking, making the habit more reinforcing. Others metabolize alcohol differently, which can either protect them (by making drinking unpleasant) or increase vulnerability.
What Alcohol Does to the Brain Over Time
Chronic heavy drinking physically changes the brain. Research from Johns Hopkins University found that alcohol damages neural circuits in a region critical for decision-making, causing the brain to process information less effectively. This helps explain why people with severe AUD make choices that seem irrational from the outside. The impaired judgment isn’t just a personality flaw. It reflects actual damage to the hardware responsible for weighing consequences.
The brain also adapts to the constant presence of alcohol by recalibrating its chemistry. This is tolerance: your nervous system compensates for alcohol’s sedating effects, so you need more to feel the same result. For a given blood alcohol level, a chronic heavy drinker may appear far less impaired than someone who rarely drinks. That adaptation comes at a cost. People who are tolerant to alcohol also become cross-tolerant to other sedatives, and the physical dependence that accompanies tolerance makes withdrawal genuinely dangerous.
Physical Signs of Dependence
Withdrawal is one of the clearest markers separating heavy drinking from physical dependence. Symptoms exist on a continuum. Mild withdrawal looks like tremors, anxiety, sweating, and insomnia, typically starting 6 to 24 hours after the last drink. More severe withdrawal can involve hallucinations, seizures, and a life-threatening condition called delirium tremens that involves dangerous spikes in heart rate, blood pressure, and body temperature. Alcohol is one of the few substances where withdrawal itself can be fatal.
Long-term heavy drinking also leaves visible traces throughout the body. The liver takes the most direct hit, progressing from fatty liver to inflammation to cirrhosis. But the damage extends well beyond that: chronic gastritis, inflammation of the pancreas, weakened heart muscle, nerve damage in the hands and feet, and increased cancer risk in the liver, throat, and esophagus (especially combined with smoking). Brain-specific damage can include severe memory impairment and a condition where the brain can no longer form new memories at all.
How to Tell If Your Drinking Is a Problem
Doctors use brief screening tools to flag potential problems. One of the most common is the CAGE questionnaire, a four-question checklist. Have you ever felt you should Cut down on your drinking? Have people Annoyed you by criticizing your drinking? Have you ever felt Guilty about your drinking? Have you ever had an Eye-opener, a drink first thing in the morning to steady your nerves or get rid of a hangover? Answering yes to two or more of these suggests a problem worth exploring further.
Another widely used tool, the AUDIT-C, focuses on three questions: how often you drank in the past year, how many drinks you typically had on drinking days, and how often you had six or more drinks on a single occasion. These questions are designed to catch patterns, not isolated incidents. A single rough night doesn’t define a disorder. A repeating pattern of heavy use, failed attempts to moderate, and life disruption does.
The Spectrum Matters
One reason the medical world shifted from “alcoholic” to “alcohol use disorder” is that the old label implied a binary: either you are one or you aren’t. In reality, problematic drinking exists on a gradient. Someone with mild AUD who catches the pattern early has a very different outlook than someone with severe dependence and organ damage. Both have a disorder. Both benefit from intervention. But grouping them under the same dramatic label often kept people with milder problems from recognizing themselves and seeking help.
If you recognize yourself in even a few of the symptoms listed above, that recognition itself is meaningful. You don’t need to match a stereotype of someone who drinks all day or has lost everything. The clinical threshold is just two symptoms in a year. That’s a deliberately low bar, set because early intervention works far better than waiting for a crisis.