Welcome to another edition of Mental Health Insights: Science Decoded!
Today we’re diving into a study that tackles one of the most important questions in mental health: What happens when people with psychosis continue using cannabis? The answer might surprise you – and it has huge implications for treatment and recovery.
The Big Question
So here’s the setup: We know that people with psychotic disorders like schizophrenia use cannabis at much higher rates than the general population. And we know that when they continue using after their first psychotic episode, bad things tend to happen – more hospitalizations, worse symptoms, longer stays in the hospital.
But here’re the million-dollar questions that’s been driving researchers crazy:
- Is cannabis actually causing these relapses, or is something else going on?
- Maybe people with worse symptoms just happen to use more cannabis?
- Maybe they’re self-medicating?
- Or maybe there’s some genetic factor that makes people both more likely to develop psychosis AND more likely to use cannabis?
Enter the Detectives
This is where our research team from King’s College London comes in, led by Dr. Sagnik Bhattacharyya and first author Tabea Schoeler. They followed 220 people who had just experienced their first episode of psychosis for at least two years. But here’s what makes this study brilliant – instead of just comparing cannabis users to non-users, they tracked the same individuals over time, looking at periods when they used cannabis versus periods when they didn’t.
Think of it like this: If your identical twin used cannabis for six months and you didn’t, and your twin had more relapses during those six months, that would be pretty compelling evidence that cannabis was the culprit, right? That’s essentially what they did, but with the same person over time.
The Startling Numbers
What they found was eye-opening. When people were using cannabis, their odds of having a psychotic relapse requiring hospitalization increased by 13%. Now, that might not sound huge, but remember – we’re talking about hospitalizations here, which represent the most severe outcomes.
But it gets more interesting. The researchers found what they call a “dose-response relationship.” Basically, the more consistently someone used cannabis over time, the higher their risk of relapse. People who used cannabis continuously after their first episode had a whopping 59% relapse rate, compared to only 28.5% for those who didn’t continue using.
The Smoking Gun
Here’s where the study gets really clever. The researchers used something called “cross-lagged analysis” – basically asking whether cannabis use in year one predicted relapses in year two, or whether relapses in year one predicted cannabis use in year two.
The results were crystal clear: Cannabis use predicted future relapses, but relapses did NOT predict future cannabis use. In other words, people weren’t just reaching for cannabis because they were feeling worse – the cannabis was actually making things worse.
What This Really Means
This study used what researchers call a “quasi-experimental design” – the gold standard for establishing causation when you can’t do a true experiment. And remember, they controlled for all sorts of factors that could muddy the waters – medication adherence, use of other drugs, genetic factors, family environment, you name it.
The implications are profound. As Dr. Bhattacharyya put it, these results suggest that continued cannabis use after psychosis onset is “causally associated” with increased risk of relapse. That’s scientist speak for: cannabis isn’t just along for the ride – it’s actually driving some of these bad outcomes.
The Real-World Impact
Let’s put this in perspective. Psychotic disorders like schizophrenia are among the most devastating mental health conditions. They cause more health loss than almost any other disorder, and hospitalizations are incredibly disruptive and expensive – both for individuals and society.
The study found that nearly 60% of people who continued using cannabis after their first psychotic episode ended up back in the hospital within two years. Compare that to less than 30% for those who didn’t continue using – that’s a massive difference.
The Clinical Challenge
Now, here’s the tricky part for clinicians and families. Many people with psychosis DO continue using cannabis – and getting them to stop is notoriously difficult. Current interventions have limited success. But this research suggests that helping people discontinue cannabis use after a first psychotic episode could be one of the most important things we can do to prevent future crises.
The Bigger Picture
This study came out at a fascinating time in cannabis policy. As more places legalize cannabis, we’re having lots of conversations about its safety. And for most people, cannabis probably is relatively safe. But this research reminds us that for people with psychotic disorders, the stakes are much higher.
The researchers were careful to note that this doesn’t mean cannabis causes psychosis in healthy people – that’s a different question entirely. But for people who’ve already had a psychotic episode, continuing to use cannabis appears to significantly increase their risk of ending up back in crisis.
The Takeaway
What makes this study so compelling is its methodology. By following the same people over time and comparing their periods of use with their periods of non-use, the researchers were able to control for all those pesky confounding factors that usually make it hard to establish causation.
The message is clear: for people recovering from first-episode psychosis, cannabis isn’t just a harmless recreational drug – it’s a significant risk factor for relapse that could land them back in the hospital.
Looking Forward
This research has been cited hundreds of times since publication, and it’s changed how many clinicians think about cannabis use in people with psychosis. It’s also spurred new research into better interventions to help people with psychotic disorders reduce their cannabis use.
The big challenge now? Developing effective treatments and policies that acknowledge this risk while still respecting individual autonomy and avoiding stigmatization.
Wrapping Up: That’s our deep dive into this groundbreaking study on cannabis and psychosis relapse. It’s a reminder that when it comes to drug policy and clinical practice, one size definitely doesn’t fit all. Thanks for reading this post on Mental Health Insights: Science Decoded – we’ll catch you next time with another study that’s reshaping how we understand health and behavior.
Study Reference: Schoeler, T., Petros, N., Di Forti, M., et al. (2016). Association between continued cannabis use and risk of relapse in first-episode psychosis: A quasi-experimental investigation within an observational study. JAMA Psychiatry, 73(11), 1173-1179. doi:10.1001/jamapsychiatry.2016.2427