How to Tell If Someone Is on Cocaine: The Signs to Look For

If you're trying to work out how to tell if someone is on cocaine, you're probably not doing it out of idle curiosity. Something has shifted in someone you care about, and a quiet voice in the back of your head has started asking a question you don't really want to ask. Maybe it's your partner, your son or daughter, a close friend, or someone on your team at work. You've noticed things that don't quite add up, and you're frightened of what they might mean — and frightened, too, of being wrong and unfair.

I'm Gary Clinton, a cocaine addiction specialist and CBT-qualified therapist, and I'm in long-term recovery myself. So I've seen this from both sides: I've been the worried person doing the noticing, and I've been the person doing the hiding. What I want to do here is walk you calmly through the signs someone is on cocaine — while they're high, on the comedown afterwards, and over the longer term — and to be honest with you about how easily these signs can be misread. This is about noticing patterns, not building a case against someone you love.

One thing to hold onto before we start: none of what follows is a diagnosis, and no single sign proves anything. People are tired, stressed, unwell and overworked for all sorts of reasons. What matters is the bigger picture — the cluster of things that, taken together, start to point somewhere.

Signs someone is on cocaine right now (while they're high)

Cocaine is a stimulant, and its effects come on fast and don't last long — often just twenty to forty minutes before someone wants more. That short, sharp arc is part of why the signs while high can feel so noticeable, and why people slip off to "top up". When someone is actually under the influence, you might notice:

• Suddenly wired, talkative and full of energy. A burst of confidence and chattiness that appears from nowhere — talking over people, jumping between subjects, an intensity that's a bit much for the moment.
• Grandiosity and over-confidence. Big plans, big opinions, a sense of being invincible or smarter than everyone in the room. It can tip into irritability or arrogance.
• Dilated (enlarged) pupils. The black centre of the eye looks unusually large, even in a bright room. People sometimes wear sunglasses indoors or at odd times to hide it.
• Sniffing, a runny nose or nosebleeds. Snorting irritates the nose, so persistent sniffing, congestion, or unexplained nosebleeds — especially alongside other signs — can be telling.
• Jaw clenching, teeth grinding or chewing. A tight, working jaw, grinding teeth, or chewing gum constantly to manage it.
• Frequent trips to the loo or stepping outside. Disappearing every twenty minutes or so, often to bathrooms, and coming back somehow brighter or more wound up than they left.
• Not eating and not sleeping. Skipping meals with no appetite, then being wide awake long into the night when they'd normally be flagging.
• Restlessness and fidgeting. Can't sit still, fast or pressured speech, foot tapping, a kind of buzzing energy that doesn't settle.

You might also notice the practical traces: small folded paper wraps or empty tiny bags, rolled notes, traces of white powder, or a card and a flat surface being borrowed in a hurry. I won't go into method here — the point is simply that these objects, in context, can be part of the picture.

Signs after the high: the cocaine comedown

Here's something a lot of worried partners and parents miss. You may never actually catch someone "high" — but you might see the wreckage afterwards. What comes up must come down, and the cocaine comedown can be brutal. In the hours and days after using, you might notice:

• Irritability and a short fuse. Snapping over nothing, defensive, picking fights, unable to tolerate normal everyday friction.
• Low, flat or anxious mood. A heavy crash into sadness, worry or hopelessness — sometimes well out of proportion to anything that's actually happened.
• Exhaustion and oversleeping. After being up half the night, a wiped-out day or two of catching up, often on a weekend or "duvet day".
• Withdrawing and going quiet. Cancelling plans, hiding away, not wanting to be looked at or spoken to while they ride it out.
• Cravings and edginess. A restless, on-edge quality, sometimes with a strong pull to do it all again to make the bad feeling stop.

This rhythm — bright and wired, then flat and snappish — is often the clearest pattern of all. If someone is reliably wonderful on a Friday night and unbearable by Sunday afternoon, week after week, that cycle says more than any single symptom.

That check-in is worded for the person using, but if you're reading this on someone else's behalf, it can still be useful. You can answer it as best you can on their account to get a rough sense of how serious things might be — or, far better, keep it in your back pocket to share with them gently when the moment is right. It's a softer starting point than a confrontation.

Longer-term and behavioural signs of cocaine use

Some of the most important clues aren't physical at all. They're the patterns that build up over weeks and months, and they're often what finally makes a worried partner or parent trust their gut. Is my partner using cocaine? The answer rarely arrives as a single moment — it accumulates. Look for:

• Money that doesn't add up. Cash disappearing, unexplained withdrawals, borrowing, "lost" wages, savings that quietly drain away, or vagueness and defensiveness about money that never used to be an issue.
• Secrecy and lying. Being cagey about where they've been and who with, a phone that's suddenly guarded, accounts that don't quite hold together, whole evenings that go unexplained.
• New friends and new patterns. A different crowd, late-night messages, stepping out to take calls, plans that materialise out of nowhere and end at strange hours.
• Mood swings. Big peaks and troughs — charming and generous one day, withdrawn or volatile the next — on a cycle that seems to track their use rather than real life.
• Broken promises. "Never again" said and meant, then quietly undone. Repeated resolutions that don't hold are one of the clearest signs that something has a grip.
• Things slipping. Performance dipping at work, missed commitments, neglected responsibilities, less interest in things that used to matter — often covered over with plausible excuses.

It's worth knowing that not everyone who is in real trouble looks like they're in trouble. Plenty of people hold down demanding jobs and busy lives while using — what I've written about as the signs of a high-functioning cocaine addict. With these people the cracks are subtler: the money, the comedowns and the secrecy are there, but they're well hidden behind competence. If your instinct keeps nagging despite everything looking fine on the surface, don't dismiss it.

A word of caution: these signs overlap with ordinary life

I want to be really straight with you here, because it matters. Almost every sign on this page can have an innocent explanation. Dilated pupils can be dim lighting, tiredness, anxiety or other medication. A runny nose can be a cold or hay fever. Irritability, low mood, poor sleep, weight loss and money worries are the everyday signature of stress, overwork, grief, depression and a dozen physical health conditions. Used on their own, any one of these proves nothing — and accusing someone on the strength of a single clue can do real damage to trust.

The question isn't "have I spotted the one thing that proves it?" It's "is there a pattern here that I can no longer explain away?"

So look for clusters, not isolated incidents. Look for change — a shift from how someone normally is. And look for the rhythm: the wired highs followed by the flat, irritable crashes, again and again. One odd weekend is life. The same cycle every week, with money vanishing and stories that don't hold, is a pattern worth taking seriously.

What to do if you think someone is using cocaine

So you've noticed the signs, and your gut has made its mind up. What now? The instinct is to confront — to lay out the evidence and demand the truth. I'd gently ask you not to do that, at least not like that. An ambush tends to produce denial, anger and better hiding, not honesty. Here's what tends to work better.

• Don't ambush them. Pick a calm, private, sober moment. Lead with care, not accusation: "I've been worried about you, and I want to understand what's going on," lands very differently from "I know what you're doing."
• Get yourself ready first. Understanding how to raise it without slamming the door shut is its own skill. I've written a full guide on helping someone who uses cocaine — what to say, what to avoid, and how to set boundaries without ultimatums. Read that before you have the conversation.
• Gauge the seriousness, gently. The check-in above, and the honest questions in Am I Addicted to Cocaine?, can help you understand how deep this might run — and give them a low-pressure way to look at it themselves when they're ready.
• Look after yourself too. You can't pour from an empty cup, and you can't carry another adult's recovery for them. Lean on people you trust, and get your own support in place.

And please remember the most freeing truth I know in this work: you didn't cause it, you can't control it, and you can't cure it for them — but you absolutely can influence the odds that they reach for help. Staying steady, staying kind and keeping the door open is not doing nothing. It's often the very thing that lets someone finally walk through it.

If you've recognised someone you love in this, take a breath. Noticing is the hard first step, and you've taken it. The next one doesn't have to be a confrontation or a crisis — it can simply be a quiet, honest conversation, made a little easier with the right preparation behind you.

Gary Clinton

Ireland's cocaine addiction specialist — CBT-qualified therapist, bestselling author of Never Give Up, and in long-term recovery himself. Private one-to-one help for professionals, online and worldwide.