Just a heads up, we’re going to be talking about some fairly intense subjects in this post as we’ll be mentioning mental illness and how it manifests.
Sometimes in our harm reduction chats we’ll mention that a substance has a risk of psychosis as something to watch out for, but what does that actually mean?
Psychosis 101
Psychosis is a heavily stigmatised term thanks to a gross misrepresentation of mental illness in pop culture and the media in general. The Mental Health Foundation of New Zealand describes psychosis as someone perceiving reality differently to everyone else around them.
This means that they may be:
- Seeing or hearing things that others are not
- Believe things that aren’t real for other people (the person can read peoples’ minds, someone is out to get them, the devil or god is speaking directly to them, or their AI chatbot is capable of human emotion)
- Experiencing intense paranoia
- Have disorganised thoughts and speech (racing thoughts, using words that only they know)
This is incredibly common – 1 in 10 people report having at least one psychotic-like experience in their lives. These symptoms become psychosis when it’s distressing, disrupting theirlife and their ability to function. Not being able to tell the difference between what is real for you and what’s real for the rest of the world can be debilitating and terrifying.
Read more about the prevalence of psychosis in A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder by Van Os et al, Psychlogical Medicine, 2009
and
Psychotic Experiences in the General Population: A Cross-National Analysis Based on 31,261 Respondents From 18 Countries by McGrath et al, JAMA Psychiatry 2015.
Psychosis can be caused by things like trauma or head injuries, or be a symptom of things like bipolar, dementia, and schizophrenia. We’re going to be looking specifically at substance-induced psychosis in this post.
When Things Start To Go Wrong
The first sign that something is wrong is often subtle.
Maybe someone hasn’t slept for two days and starts talking faster than usual. Maybe they suddenly become convinced people nearby are talking about them. Maybe they begin noticing hidden meanings in ordinary things — song lyrics, conversations, the way strangers glance in their direction.
At first it might seem like they’re just having a strange night.
But sometimes those experiences keep intensifying.
“I remember sitting with someone who thought they had died. They were completely convinced they were no longer alive. That went on for more than ten hours.”
“At first I got this strong hunch that some people at the party might have been undercover cops trying to spy on me. Throughout the night I started seeing things like a radio ear piece on one of the women’s ears, a voice recorder in another guy’s hand. Over the next couple of months I started getting suspicious that friends I’ve known for years might also be working for the police to get me. I started acting very paranoid, doing things like following the cables coming out of the alarm sensors in our flat thinking they might be surveillance devices.”
Psychosis can be deeply unsettling for the person experiencing it and for the people trying to help.
“You can’t change the fact that they’re in psychosis, but how you approach them can completely change what that experience is like.”
Sometimes the most effective response begins with something simple.
“A distressed person came into our service screaming at the top of their lungs about Satan. Someone I was working with just said, ‘Hey, looks like you’re having a rough time.’ and started chatting with them in a calm tone like you’d use to greet someone sitting at a bus stop. Within minutes they were talking instead of screaming.”
Moments like these are why harm reduction conversations sometimes include warnings about substance-induced psychosis.
What Happens In The Brain During Psychosis?
Psychosis involves changes in how the brain processes meaning and significance. One of the strongest findings in neuroscience is dysregulation of dopamine signalling. Dopamine helps the brain decide what is important by firing receptors when significant events happen.
Read about dopamine’s role in event-tagging in Dopamine in motivational control: rewarding, aversive, and alerting by Bromberg-Martin et al, Neuron, 2011
When dopamine signalling becomes unstable, the receptors can fire at random instead of when they’re meant to. This makes the brain assign too much importance to ordinary events such as:
- A coincidence may feel meaningful, like seeing someone in a blue t-shirt right before narrowly missing being hit by a car crossing the road.
- A passing comment, song lyric, or passage in a book may feel like a hidden message meant specifically for them.
The brain then tries to interpret these dopamine messages of importance. If there’s no real-world importance your brain will try to fill in the gaps. Sometimes those interpretations are delusional explanations that aren’t in line with reality.
If we go back to the blue t-shirt example, if the dopamine mis-fires when the person sees the blue t-shirt person their brain will see them as important and tie them to the context of almost being hit by a car. This can create the delusion that the person in the blue t-shirt was responsible for the car almost hitting them.
Sleep deprivation can worsen this process. Extended periods without sleep can disrupt perception, emotional regulation, and reality testing.
Read more about dopamine’s role in psychosis in The dopamine hypothesis of schizophrenia: version III–the final common pathway by Howes and Kapur, Schizophrenia Bulletin, 2009
and
Psychosis as a state of aberrant salience: a framework linking biology, phenomenology, and pharmacology in schizophrenia by Kapur, The American Journal of Psychology, 2003
Read more about sleep-deprivation and its affects on reality perception in Severe Sleep Deprivation Causes Hallucinations and a Gradual Progression Toward Psychosis With Increasing Time Awake by Waters et al, Frontiers in Psychiatry, 2018
Substance-Induced Psychosis
Like the name suggests, substance-induced psychosis (SIP) happens when a substance is involved in triggering the symptoms we’ve discussed above.
This may happen when:
- A substance strongly affects dopamine or serotonin systems
- Very large doses are taken
- Drugs are used repeatedly over long periods
- Severe sleep deprivation occurs
- Someone has an underlying vulnerability to psychosis
Use of psychedelics in intense environments (i.e. music festivals), use of cannabis, sustained use of stimulants over multiple days, and lack of sleep are well-known triggers.
“When my GP put me on SSRIs for the first time it was wild. Thanks to the meds I felt euphoric the entire time, but I had the worst insomnia, which made things go a little weird. The first day I took them I was awake for 56 hours. When it was coming to the end of the second day of being awake I was at my desk at work when I saw a vine grow past me from the plant on my boss’s desk that was a metre behind me. I went home, slept for 3 hours, then was awake for another 17. As you do.”
The main difference between SIP and the kind of psychosis that’s a symptom for schizophrenia and other conditions is that SIP wears off after a period of time. That period can be months, but the person experiencing SIP will eventually come back to shared reality. However there is a strong correlation between SIP and later diagnosis of related psychiatric conditions; more on that later.
In many cases, substance-induced psychosis resolves once the drug leaves the body and the brain stabilises.
Episodes may last hours, days, or occasionally weeks. Symptoms, including delusional or paranoid thoughts can last for months or even pop up occasionally over many years.
“It’s been 12 years now and I still get the occasional moment where those thoughts will come back. I’ll be standing there chatting with someone and then boom it’s like a bolt of lightning hits me and I connect all the dots that makes me believe for a second that this person could be an undercover cop trying to get incriminating information out of me. I don’t even have to be doing anything illegal at the time! I just get totally convinced that this person is undercover. Then a moment later I’ll realise how literally crazy that thought is, but for a split second it feels so real and logical.”
We couldn’t find much data for the number of people in Aotearoa who experience SIP. We found one study with a cohort of 2,400 but they were all aged 15-25. Of that cohort, 7% (174) of people first episode of psychosis was SIP. We couldn’t find numbers for older people experiencing SIP.
Read the study: Evolution of first episode psychosis diagnoses and health service use among young Māori and non-Māori—A New Zealand national cohort study by Carr et al, Early Intervention in Psychiatry, 2022
It does seem that psychosis is fairly common with every 3 in 100 people in Aotearoa having a psychotic episode at least once in their lives.
If we do some extrapolation and use the youth study’s 7% SIP against the population number from the last census, it’s possible that up to 11,250 people in Aotearoa have experienced SIP as their first psychotic episode.
Most Substances Can Cause Psychosis
SIP happens when neurotransmitters are dysregulated, particularly the serotonin and dopamine pathways. Most of the drugs that people take for fun act on these pathways to provide their desired effects. Which means that SIP can be caused by most substances on the market, including alcohol.
“Most of the drug induced psychosis I’ve experienced has been from the combination of psychedelics, cannabis, and a stressful environment. However, one time it happened when I was using psychedelics, stimulants, alcohol, and benzos all together in moderate doses over a really long party. It probably didn’t help that I didn’t sleep.”
People can also experience psychosis when they’re going through withdrawal while coming off a substance. The most common example of this is delirium tremens, which is the rapid- onset of hallucinations, confusion, and shaking that happens when people who have severe alcohol dependency are suddenly cut off. This can also be life-threatening.
Read more about alcohol-induced psychosis
Read more about cannabis-induced psychosis
Read more about cannabis withdrawl psychosis
Isn’t that just tripping tho?
Not quite. Sensory distortions or hallucinations can be desirable. Psychedelics like acid, mushrooms, or DMT and dissociatives like NOS or ketamine will definitely screw with how you perceive reality. It’s why people take them. The key difference is that psychosis isn’t desirable or sought after, and actively harms the person going through the experience.
Some people describe psychedelic experiences as allowing them to examine patterns in their thinking.
“It helped break down connections I’d learned between things, social rules, assumptions about myself, so I could examine them again.”
But these experiences can sometimes move in darker directions.
“Sometimes I’d start seeing connections that weren’t really there… building a narrative out of fear and memory.”
The key difference between psychedelic experiences and psychosis is loss of insight and persistence of symptoms after the drug should have worn off. At this point it’s definitely life-disrupting and no longer a desirable experience.
“It felt like looking behind the curtain of reality… another whole narrative playing out that didn’t correspond to my normal life.”
There hasn’t been a lot of recent research into what the tripping-to-SIP tipping point is. Some studies seem to think it’s dependent on the amount of drugs people are taking and some studies seem to think it’s dependent on the length of time people are taking drugs. Some studies say you need to have a genetic predisposition for SIP like you do for bipolar or schizophrenia. And then there’s the added complication of Hallucinogen Persisting Perception Disorder (HPPD) – which can be distressing, but doesn’t interfere with normal functioning like psychosis.
All we can really say for sure is that it happens in some people that take drugs sometimes and there’s no definite predictor just yet.
Read more about challenging experiences after taking psychedelics in Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences by Carbonaro et al, Journal of Psychopharmacology, 2016
and
Ayahuasca, dimethyltryptamine, and psychosis: a systematic review of human studies by dos Santos et al, Therapeutic Advances in Psychopharmacology, 2017
Can SIP cause things like bipolar or schizophrenia?
If we’re being honest, we don’t know yet whether SIP definitively causes these long term disorders. What we know at the moment (2026) is that many people fully recover after their first episode, however long term studies show a minority later develop schizophrenia-spectrum or bipolar disorders.
Research suggests roughly 25–35% of individuals with substance-induced psychosis later receive such diagnoses, though risk varies depending on the substance and individual factors.
Some researchers believe substances may sometimes trigger the first episode in people who already have underlying vulnerability. We do know for sure that there is a strong link between cannabis use and psychosis. Cannabis-related psychosis appears to have relatively higher conversion rates than other substances, potentially over 47%.
There’s also a high number of people that have taken drugs and never had an episode of SIP.
Because the correlation is so high and the research just isn’t there yet, we can’t rule it out entirely. So if you have reality-distorting medical conditions in your family’s medical history be careful with what you do with your brain, eh?
Read more about the correlation between first-episode SIP and schizophrenia in Transition of Substance-Induced, Brief, and Atypical Psychoses to Schizophrenia: A Systematic Review and Meta-analysis by Murray et al, Schizophrenia Bulletin, 2019
Read more about the correlation between first-episode SIP and schizophrenia and bipolar disorder in Rates and Predictors of Conversion to Schizophrenia or Bipolar Disorder Following Substance-Induced Psychosis by Starzer et al, The American Journal of Psychology, 2018
Cannabis and Psychosis Risk
Among commonly used substances, cannabis is one of the drugs most consistently associated with psychosis risk.
Risk appears to increase when:
- THC levels are high
- Use is frequent or daily
- Use begins during adolescence
- There is a personal or family history of psychotic disorders
One large European study found daily use of high-potency cannabis was associated with roughly four times greater odds of psychotic disorder compared with non-users.
Read the study: The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study by Di Forti et al, Lancet, 2019
This does not mean cannabis inevitably causes psychosis. Reefer madness is not a Thing, and most people use cannabis without experiencing it. However, it appears to increase risk in individuals who already have a predisposition to psychosis in their family’s health history.
Adolescents may also be particularly sensitive because the brain is still developing. The majority of people with non-substance induced psychosis have their first episode while they’re going through puberty as their brain activity is going off the charts. If your brain is in overdrive already, adding something that is likely to cause psychosis in adults is probably going to increase the risk of having an episode.
Read more about adolescent vulnerability to psychosis in Adolescent Neurodevelopment and Vulnerability to Psychosis by Patel et al, Biological Psychiatry, 2022
What To Look Out For
Early warning signs that someone may be experiencing substance-induced psychosis can include:
- severe sleep deprivation
- escalating paranoia
- believing ordinary events contain hidden meanings
- disorganised or racing thoughts
- speaking quickly or using made-up words
- extreme emotional swings
Recognising these signs early can sometimes prevent situations from escalating.
If someone near you appears to be entering psychosis:
- Stay calm. Your tone and body language matters. Stand or sit beside them instead of directly in front of them. Don’t stare at them. Ask casual questions to get an idea what is happening for them.
- Avoid arguing about their beliefs. Direct confrontation of delusions often increases distress. Believing that what they’re experiencing is real for them will help them feel like you understand them and they can trust you.
- Reduce stimulation. Move somewhere quieter if possible. If you’re at an event and there’s a chillout space then try to take them there. Even better, if you’re at a festival which has services like our bffs at Psycare or Deepspace that is the perfect place. Their teams are trained to help people having difficult experiences and will know what to do
Seek medical help, particularly if the person:
- appears extremely distressed
- may harm themselves or others
- continues experiencing symptoms long after the substance should have worn off
If you’re not at an event or festival, there are plenty of organisations that you can talk to if SIP is affecting you or someone you know. Our friends at Healthify have them all collated onto one very handy page:
Healthify’s Support contact page
Whether you’ve experienced SIP or you’ve been supporting someone experiencing SIP then you may want to reach out to support at the above organisations after the experience too. Take time to process your experience and talk it through with people you trust.
Further reading
Substance-Induced Psychoses: An Updated Literature Review by Fiorentini et al, Frontiers in Psychiatry, 2021
Discussing the concept of substance-induced psychosis (SIP) by Bramness et al, Psychological Medicine, 2024
Substance-Induced Psychosis: Diagnostic Challenges and Phenomenological Insights by Ricci et al, Psychiatry International, 2024