Would you notice if your teen changed? Not something big; just the little things. They’re in their room more, and the conversations that used to flow now fall flat. According to Perry Clayman, managing director and founder of Rehab Today, parents often feel the change before they actually see any signs.

“Teens won’t usually admit they’re trying drugs, and at their age, curiosity and experimentation are natural. If it’s just that – experimentation – you’ll probably never even know it,” he says. “The issue is when it turns into a habit or a coping mechanism – that’s when you’ll start to notice something’s off.”

Clayman has spent decades helping families through addiction and shares the early signs that parents should keep an eye out for:

1. They’re not themselves lately

Every teenager has their moods. But sometimes the shift feels sharper; different. They’re suddenly defensive, or quieter than usual.

“When a laid-back teen starts snapping, or one who’s usually chatty goes silent, listen to that gut feeling,” Clayman says. “You don’t need to panic. Just notice what feels out of character.”

It can be easy to brush off changes as ‘just teenage stuff’. But if that new mood lingers for weeks and you can’t quite place why, that’s when it’s time to ask – gently – what’s really going on.

2. Schoolwork starts slipping (and they don’t seem to care)

A missed deadline isn’t unusual. But when late homework turns into skipped classes or constant tiredness, it’s time to start asking questions.

“When motivation drops off completely, that’s often when drug use quietly shows up first,” Clayman explains. “It affects focus and drive – the things school depends on.”

Sometimes you’ll hear excuses, sometimes just a shrug. Either way, a drop in effort, alongside changes in mood or sleep, shouldn’t be ignored. 

3. Small physical changes start to add up

Red eyes. A loss of appetite. Sleeping at odd hours. Each one on its own might mean nothing. But together, they start to tell a story.

“You might also notice mints, air fresheners or eye drops appearing around the house,” says Clayman. “Those little things often have a reason; they’re there to hide something.”

Of course, these signs alone don’t prove anything. But when they appear alongside emotional or social changes, that’s when parents should look closer.

4. Money suddenly goes missing

Teenagers need money; that’s nothing new. But if cash starts going missing, or they’re suddenly asking for more than usual without being able to explain why, that’s worth a closer look.

“Drug use costs money, and sudden spending changes can be one of the first red flags,” says Clayman. “Sometimes it’s tiny amounts at first. What matters is the pattern.”

And while it’s tempting to react in frustration, Clayman says calm questions get better answers. “Anger shuts teens down. Curiosity opens them up.”

5. New friends, new habits, new rules

Friend groups naturally change, but when it happens overnight (and your teen suddenly won’t say who they’re with) that’s worth paying attention to. “If your teen stops seeing old friends suddenly or becomes secretive about new ones, that can be a sign of something deeper,” says Clayman.

It’s not always a bad crowd; sometimes it’s just new influences. But sudden secrecy about plans or names can signal they’re looking for people who won’t question new behaviours.

6. Language and habits that shift overnight

You might hear slang or phrases you don’t recognise, or see your teen hide their phone faster than usual. “When language changes suddenly, or they become protective of their messages, it can sometimes point to experimentation,” Clayman says.

Still, the best approach isn’t confrontation. Ask what something means, even if you feel out of touch. Showing interest rather than suspicion keeps the conversation alive; and that’s what matters most.

Talk early before it’s serious

Clayman says the best time to talk about drugs is before there’s a reason to worry. “Use what’s around you,” he suggests. “If it comes up in a show or on social media, that’s your cue. Keep it casual, not heavy. It helps normalise the topic.”

And if you do find out they’ve tried something? “Stay calm,” he says. “Experimentation doesn’t mean addiction; and it doesn’t mean you’ve failed as a parent. What matters is how you respond.”

Patience goes a long way. With the right support, most young people move past it and learn from the experience. Early action and calm conversations make all the difference.