Drug-induced psychosis is when a drug makes someone lose touch with reality. They may see or hear things that are not there, or hold fixed false beliefs, most often that people are watching them or planning to hurt them. Syabu (methamphetamine), the drug behind most addiction cases recorded in Malaysia, is a common cause, and cannabis and other drugs can cause it too. It usually eases within days to weeks once the drug is stopped, but it needs urgent medical assessment, and if anyone is in danger, call 999.
What drug-induced psychosis is
Psychosis is a medical term for losing touch with what is real. The NHS describes its main features:
- Hallucinations: seeing, hearing, smelling, tasting or feeling things that do not exist outside the person's mind.
- Delusions: an unshakeable belief in something untrue. The most common type is persecutory, where the person believes someone is out to harm them. Some people believe they have special powers.
- Confused thinking: fast, constant speech, jumping between topics, or losing the thread mid-sentence.
People with psychosis are often unaware that what they are experiencing is not real, which is why they can be so frightened. When a drug causes it, during use, heavy use or withdrawal, doctors call it drug-induced or substance-induced psychosis.
Common causes
Syabu and other stimulants
Syabu matters most here because it is so widely used: amphetamine-type stimulants now make up 73 per cent of the drug addiction cases recorded by the National Anti-Drugs Agency (AADK). The WHO guidelines note that people who use large amounts of stimulants, particularly methamphetamine, can develop paranoia, disordered thoughts and hallucinations.
A 2014 study of methamphetamine-dependent patients in Malaysia found that 47.9 per cent had experienced psychotic symptoms at some point, and 13 per cent had them at the time of the study. Heavier use, depression and bipolar disorder were all linked to a higher risk. The authors concluded that everyone with methamphetamine dependence should be checked for psychotic symptoms.
Cannabis
According to NIDA, cannabis can cause a temporary psychotic episode in some people, especially at high doses. It has also been linked to earlier onset of psychotic illnesses such as schizophrenia in people who are already at genetic risk.
Other drugs, alcohol and withdrawal
The NHS lists cocaine, amphetamine, mephedrone, MDMA (ecstasy), LSD, magic mushrooms and ketamine among drugs that can trigger psychosis. Heavy drinking can too, and stopping alcohol or drugs after long-term use can cause psychosis through withdrawal.
Signs to look for
- Talking to or answering voices, or reacting to things no one else can see.
- Paranoia: believing they are being followed, spied on, poisoned or plotted against, often by family.
- Fear and agitation that seem out of proportion to anything happening around them.
- Speech that is fast, jumps about or makes little sense.
- Odd beliefs about themselves, such as having special powers or a special mission.
Dr Rusdi Abd Rashid of the University of Malaya Centre for Addiction Sciences told Kosmo in 2021 that people in stimulant psychosis can no longer tell reality from hallucination, and may act in extreme ways out of fear. Mind, the UK mental health charity, notes that responding calmly can help stop anger escalating.
What to do in the moment
Your safety, and the safety of others in the house, comes first.
- If the person is threatening to harm themselves or anyone else, or has a weapon, call 999 now.
- Keep your voice calm and low. Use plain words and short sentences, and give them time to answer.
- Do not argue about the voices or the beliefs. Mind advises supporting how the person feels, without confirming or challenging what they believe. For example: "I can see you are frightened. I am here."
- Keep the room quiet, with as few people as possible. Turn off the television and loud music.
- Give them space and keep a clear path to the door for both of you.
- If it is safe, quietly move knives or other objects that could be used to hurt someone.
- Do not give them alcohol or other drugs to calm them down.
Even when the person seems calmer, they still need a doctor. Take them to the nearest hospital emergency department, or call 999 if they will not go and you are worried about anyone's safety. For support and advice when no one is in immediate danger, the Ministry of Health's mental health line, Talian HEAL, is on 15555.
How long it lasts
For methamphetamine, a 2017 clinical review in Current Psychiatry says acute symptoms usually last 4 to 7 days after the drug is stopped. They can go on for several weeks, and in some people psychosis persists long after they have stopped using. Cannabis psychosis is usually temporary.
Antipsychotic medicines can ease anxiety within hours, but the NHS says they can take several days or weeks to reduce the psychotic symptoms themselves.
The link with ongoing use
Psychosis tends to come back when the drug comes back. Symptoms can return with renewed use or with stressful life events, and NIDA notes that heavy drinking and stress raise the odds of methamphetamine psychosis returning in someone who has had it before.
Some people go on to develop a longer-term illness. A 2020 review that pooled studies from several countries found that about one in four people treated for substance-induced psychosis were later diagnosed with schizophrenia. The rate was about one in three after cannabis-induced psychosis and about one in five after amphetamine psychosis. These are averages across studies and cannot predict what will happen to any one person. They are still a strong reason to stop the drug and stay under psychiatric follow-up.
Treatment: psychiatric care first, then the drug use
- The psychosis itself. This is a medical emergency until a doctor has assessed it. The NHS says antipsychotic medicines are usually the first treatment. For severe agitation, the WHO guidelines advise calm, practical handling first and calming medicine if that is not enough. Talking therapies such as cognitive behavioural therapy (CBT, which works on the link between thoughts, feelings and actions) and family sessions can help afterwards.
- The drug use behind it. Once the psychosis has settled, the dependence needs treating, or the cycle repeats. There is no approved medicine for methamphetamine dependence, according to NIDA, so this treatment is psychological: CBT, motivational interviewing, contingency management (small rewards for drug-free tests) and support groups. See our page on syabu addiction treatment.
Dual diagnosis
Many people have a mental health condition alongside their drug use, which is called a dual diagnosis. AADK recorded 5,030 people with drug addiction between January and March 2026, and 1,346 of them also had a mental health disorder. AADK's director-general described the problems seen as including depression and states close to hallucination. When both conditions are present, they need treating in the same plan. Our page on dual diagnosis treatment explains how, and our article on depression and addiction covers the most common pairing.
Common questions
How long does drug-induced psychosis last?
After methamphetamine, acute symptoms usually ease within about a week of stopping, although they can last several weeks. In some people symptoms persist much longer, so everyone needs a psychiatric assessment and follow-up.
Can drug-induced psychosis become permanent?
For most people the episode settles. A 2020 review found that about one in four people treated for substance-induced psychosis were later diagnosed with schizophrenia, with higher rates after cannabis. Symptoms tend to return with renewed use, so stopping the drug and staying under a psychiatrist's care matters.
What does meth psychosis look like?
Usually paranoia: believing people are watching, following or planning to harm them, along with hearing voices or seeing things. The person may be terrified, agitated and convinced it is real. It can happen during heavy use and sometimes continues after stopping.
Can weed cause psychosis?
Yes. Cannabis can cause a temporary psychotic episode in some people, especially at high doses, and in people at genetic risk it has been linked to earlier onset of illnesses such as schizophrenia.
What should I do if someone on drugs becomes violent?
Get yourself and others to safety and call 999. Do not try to restrain them or argue with what they believe. Once everyone is safe, they need medical assessment in hospital.
How Salus can help
Psychosis needs emergency or hospital care first. For the drug use behind it, Salus offers a private, confidential, voluntary 90-day residential programme for adults aged 18 and over in Cyberjaya, Selangor. Every guest has a medical, psychiatric and psychological assessment on arrival, withdrawal is managed alongside medical care, and a Salus Clinician plans daily life alongside that medical care. The cost is RM7,000 per month, all-inclusive: private room, meals, 24-hour care and medical oversight, individual and group therapy, family sessions and an aftercare plan.
Families can call first, before the person agrees to anything. Call or WhatsApp Salus for a confidential conversation about what has happened and what the options are.
This article is general information, not medical advice.
