The most common signs of drug use in an adult are changes you notice over weeks: sleep and appetite that no longer make sense, money that keeps disappearing, a shift in mood and friends, and a person who has become secretive about where they go and what they do. Physical clues, such as red eyes, very small or very large pupils and weight loss, can point to particular drugs. No single sign proves anything, but a cluster of them that keeps going is worth acting on.
This guide covers what to look for, the clues that go with the drugs most used in Malaysia, and what to do once you are worried.
Why the signs are easy to miss
Drug use in Malaysia is mostly an adult problem. The National Anti-Drugs Agency (AADK) recorded 191,832 people in 2025, and 112,632 of them were aged 19 to 39. Another 72,590 were aged 40 to 59. So the person you are worried about is far more likely to be an adult in their twenties, thirties or forties than a schoolchild.
Many of these signs also have other causes. Health guidance from HealthLinkBC notes that stress at work, depression and other health problems can look the same. So look for a pattern over time, and treat any one sign as a reason to pay closer attention.
Behavioural signs
- Sleeping at odd hours, or not sleeping at all, and eating much more or much less than before.
- Missing work, losing a job, or falling behind with study.
- Dropping old friends and hobbies for a new circle you never meet.
- Lying, secrecy, and explanations that change from day to day.
- Letting hygiene and appearance slip.
- Arguments at home that never used to happen.
- Trouble with the police or with people they owe.
Money signs
Money problems are among the clearer signs, because they are hard to hide for long. Watch for frequent requests for money with no clear reason, unpaid bills, borrowing from relatives, and valuables or cash going missing from the house. Singapore's Health Promotion Board lists regular, unexplained requests for money among the signs to look out for.
Mood signs
- Mood swings that are bigger and faster than usual.
- Irritability, especially when you ask questions.
- Loss of interest in the future, in plans and in things they used to care about.
- Anxiety, suspicion or paranoia (believing people are watching or plotting against them).
Physical signs and things around the house
- Red or watery eyes, sometimes hidden behind sunglasses indoors.
- Pupils that are pinpoint small, or wide even in bright light.
- Weight loss or loss of appetite.
- A cough, sore throat or constant tiredness.
- Needle marks on the arms or elsewhere.
- Burnt pieces of foil, small plastic bags, needles, or pipes and bottles that have been altered.
Clues linked to particular drugs
These are the effects reported for each drug. They can help you make sense of what you see, though only a medical assessment can confirm it.
Syabu (ice, methamphetamine)
Syabu, the Malaysian name for crystal methamphetamine, is the drug behind most cases AADK records: 139,909 of 192,857 people in 2024 were linked to amphetamine-type stimulants. During use, people often talk fast, seem full of energy and confidence, barely eat, grind their teeth and have wide pupils. The crash afterwards brings exhaustion, long sleep, irritability and low mood. With regular use come weight loss, bad teeth, poor sleep and, in some people, paranoia and hallucinations. Our syabu treatment page explains how this is treated.
Heroin and other opioids
Heroin brings drowsiness, "nodding off" mid-conversation, slurred speech, slow breathing and pinned (very small) pupils. Long-term use can bring constipation, dental problems and damaged veins. Withdrawal usually starts within 6 to 24 hours of the last dose, with a runny nose, yawning, sweating, goosebumps, aches, diarrhoea and strong cravings.
Ganja (cannabis)
Look for red eyes, dry mouth, a big appetite, slow reactions and poor short-term memory. Large amounts can bring anxiety or paranoia. The US National Institute on Drug Abuse (NIDA) says studies estimate 22 to 30 per cent of people who use cannabis have cannabis use disorder, meaning their use causes them real harm or distress.
Ketum
Ketum is drunk openly, so families often overlook it. In a Universiti Sains Malaysia study of 293 users in Penang, Kedah and Perlis, 55 per cent were severely dependent. Asked about stopping, 64 per cent reported sleep problems, 67 per cent became nervous and 72 per cent could not control the urge to drink it. People drinking four or more glasses a day were far more likely to be severely dependent.
Pills (Erimin 5 and other sedatives)
Erimin 5, sold on the street, usually contains nimetazepam or etizolam, both sedatives in the benzodiazepine family. Signs include heavy drowsiness, slurred speech, confusion, poor balance and memory gaps. Mixed with alcohol or heroin, these pills can slow breathing dangerously. Our article on sleeping pills and cough syrup misuse covers this in more detail.
Signs of drug use in teenagers and young adults
Families often search for signs in teens. The signs are much the same at any age, with more weight on school: falling grades, missed classes, and money or belongings going missing. AADK recorded 1,213 people aged 13 to 18 in 2025, a small share of the national total.
Salus works with adults aged 18 and over. If the person is younger, start with your family doctor or a government health clinic. If they are a young adult, the rest of this guide applies.
When it is an emergency
Call 999 straight away if the person:
- cannot be woken, has pinpoint pupils or is breathing slowly or with difficulty, which are the signs of an opioid overdose the World Health Organization lists
- has a seizure
- is seeing or hearing things, is very paranoid, or is a danger to themselves or others.
What to do next
- Write down what you have seen and when. Dates help a clinician, and they help you stay specific when you talk.
- Get advice before you speak to them. A confidential call to someone who works with addiction helps you plan.
- Choose a calm moment, when they are sober, and talk about what you have seen and how it worries you. Our guide on talking to someone about getting help covers that first conversation.
- Read our practical guide on how to help someone with a drug addiction, which covers money, boundaries and relapse.
What not to do
- Do not confront them while they are high or coming down. You will not be heard.
- Do not search, accuse and lecture in one go. It usually ends in denial and a closed door.
- Do not flush pills and expect them to stop at once. Sudden withdrawal from sedative pills can cause seizures, so get medical advice first.
- Do not keep giving money you cannot account for.
- Do not wait until you are completely sure before asking for advice.
Common questions
What do your eyes look like when you take drugs?
It depends on the drug. Heroin and other opioids make the pupils very small. Syabu and other stimulants make them wide, and the person may be sensitive to light. Ganja tends to make the eyes red. Eyes alone are not proof, because light and tiredness change them too.
How can I tell if someone is on syabu?
The pattern is usually days of little sleep, fast talk and hardly any eating, followed by a crash of heavy sleep and irritability. Over months, weight loss, bad teeth and suspicion of others often follow. Pupils are often wide during use.
Could it be depression rather than drugs?
It could be either, or both. Low mood, withdrawal from friends and poor sleep can come from depression, stress or other illness. A medical and psychiatric assessment is the way to find out, and many people need help with both.
Should I search their room or phone?
Finding something may confirm your fear, but it rarely leads to a good conversation. Talking about the behaviour you have seen is usually more useful, because it is harder to argue with.
How Salus can help
Salus runs a private, confidential, voluntary 90-day residential programme for adults aged 18 and over in Cyberjaya, Selangor. Each guest has a medical, psychiatric and psychological assessment on arrival, and withdrawal is managed alongside medical care. It costs RM7,000 per month, all-inclusive: a private room, meals, 24-hour care and medical oversight, individual and group therapy, family sessions and an aftercare plan.
You can call before the person has agreed to anything. Describe what you are seeing and we will talk through the options in confidence. Call or WhatsApp Salus.
This article is general information, not medical advice.
