What is drug-induced psychosis?

Drug-induced psychosis is when someone experiences a psychotic episode that is triggered by using drugs.

During a psychotic episode, the person loses touch with reality and may act differently than their usual self. This can be a frightening experience for the person and the people they may be with.

In this article, we look at what drug-induced psychosis is, when it’s more likely to occur and how to support someone.

How can you tell if someone is experiencing a drug-induced psychosis?

Drug-induced psychosis can look like a person who:

• speaks in a confusing way, such as very quickly or without making sense
• acts odd or may be unpredictable, hostile or aggressive
• has unusual emotional responses, such as showing very little emotion or having trouble expressing feelings
• appears lethargic or unmotivated
• withdraws from others
• seems fearful, suspicious or anxious, when there’s no obvious reason for it.¹

What does drug-induced psychosis feel like?

When someone is experiencing a drug-induced psychosis, they can find it difficult working out what is real and what is not.

This is usually caused by three symptoms:

• Hallucinations – sensing things that aren’t there, such as hearing voices, seeing things others can’t see, or feeling sensations without a physical cause.
• Delusions - false beliefs that are not based in reality. These may include paranoia (e.g. believing someone is watching or trying to harm them) or unusual beliefs about the world or themselves.
• Impaired thinking (cognition) – this can impact speech, memory, emotions, behaviour and decision-making. The person may have trouble concentrating, thinking clearly or expressing themselves.^{2, 3}

These symptoms can begin suddenly or develop more gradually. They can last for several hours or days and then start to fade as the drug wears off and leaves the body.

Can it be treated?

Yes, most people recover from drug-induced psychosis. In rare situations, someone who experiences drug-induced psychosis may continue to have mental health issues, but support and treatment can help them recover.

Treatment may include:

• stopping use of the drug that triggered the psychotic episode
• taking medication to help with symptoms, like antipsychotics or benzodiazepines
• counselling to help address underlying issues, like trauma or mental health problems
• support for alcohol or other drug dependence (e.g. rehabilitation services).^3-5

What drugs can cause psychosis?

Many different drugs can cause psychosis, especially when taken in large amounts, mixed with other substances or if used over a long period.^{3, 5-7}

The substances most likely to cause psychosis are:

• cannabis
• psychedelics, such as LSD and magic mushrooms
• amphetamines (including crystal methamphetamine)
• cocaine.

MDMA, synthetic cannabinoids and dissociatives like PCP, ketamine and DXM can also trigger psychosis.

Alcohol can cause psychosis when used in very large amounts or during withdrawal.

Also, some prescription medication, including opioids, may play a role in causing psychosis if they are taken in high amounts, or if use is suddenly stopped.^{3, 5, 6}

Can drug-induced psychosis lead to schizophrenia?

For some people the symptoms of a drug-induced psychosis can continue long after the drug wears off.

In some cases, drug-induced psychosis can be the first sign of a longer-term mental illness like schizophrenia or bipolar disorder.⁸ Genetics and family history play a strong role.^9-11

In other cases, people may start using drugs to ease the symptoms of psychosis or mental illness.¹²

The three substances most linked to schizophrenia are:

• Cannabis – can increase the risk of developing schizophrenia, particularly for teenagers, males and those with a family history of schizophrenia.^7,11 Using cannabis frequently from a young age or with strong THC content makes the risk higher.^7,11 People who use cannabis have nearly three times the risk of developing schizophrenia, with the risk almost doubling if they start using cannabis in their teenage years.^11,13 While using cannabis alone is unlikely to directly cause schizophrenia, it can act as a trigger for those already vulnerable, bringing schizophrenia on earlier.¹⁴
• Psychedelics – about one in four people who are admitted to hospital for the first time with psychosis after using psychedelics will develop schizophrenia.¹³
• Amphetamines – about one in five people with an amphetamine-related psychosis go on to be diagnosed with schizophrenia.¹³

For most people however, trying a drug once or every once in a while, is unlikely to cause psychosis or lead to schizophrenia.

How can I help?

If you’re with someone who is experiencing signs of psychosis, stay calm and keep them safe.

If they’re experiencing hallucination or delusions, remain respectful and non-judgemental – understand that what they are experiencing is real for them. Avoid agreeing, arguing, dismissing, laughing at or ridiculing their experiences, as this can intensify what they’re going through.²

If the person is very distressed, agitated or severely hallucinating, call an ambulance on triple zero (000). Emergency services are there to help and can provide instructions over the phone.

If the person gets aggressive, violent or threatens to hurt themselves or someone else, move yourself and others to a safe place and call the police on triple zero (000).

You can also call a mental health crisis support line in your state or territory for help.

If you are wondering how you can provide ongoing support to someone who has experienced psychosis, you can find information in the resources listed at the end of this article.

How can I reduce the risk of drug-induced psychosis?

• Avoid use of cannabis until adulthood. Young people should delay using cannabis until age 25 to reduce their risk of psychosis, because of the impact cannabis has on brain development.^7,11 Young adults should also avoid cannabis if they have a family history of psychosis.^7,15
• If you use cannabis, you can lower your risk of cannabis-induced psychosis by avoiding smoking or vaping cannabis, choosing cannabis products with lower THC, and reducing how often and how much you use.⁷
• Learn the facts about any drugs you’re thinking of taking. To find information about different substances you can:
  • use our Drug Info Bot dib
  • search for the drug on Drug Facts
  • text the name of the drug to 0439 835 563 (via Text the Effects service)
  • test your drugs using a pill testing (drug checking) service if available, to find out how strong they are and what they contain. Drugs are often mixed with other unknown substances.
• Start low, go slow – try a little bit first to see how you feel. Wait until the expected peak effects (this can range from 30 minutes to 2 hours depending on the drug) before deciding whether to take more. This reduces the risk of overdose or overwhelming effects.
• Check in on your mood before taking a drug (the ‘set’). If you're feeling down, depressed, or anxious, using alcohol or other drugs can intensify these feelings and lead to a bad experience.
• Use in a safe environment with people you trust (the ‘setting’). The environment you’re in can affect how you experience a drug’s effects. Use in an environment where you feel safe, familiar and relaxed. Be with someone you trust if things go wrong. Alcohol and other drugs can prevent you from thinking clearly, so stay with your friends, they can look out for you if you find yourself in uncomfortable or risky situations.
• Avoid mixing drugs. Mixing some drugs together can increase your risk of having a bad experience, for example mixing amphetamines with MDMA may increase the risk of feeling anxious or paranoid.

Further resources

• Orygen - Helping someone with psychosis and young people
• Headspace – What is psychosis?
• SANE – Cannabis and psychosis 
• NDARC – Methamphetamine psychosis

This article has been reviewed by the Matilda Centre for Research in Mental Health and Substance Use, University of Sydney.