Cannabis Science

Can Weed Cause Serotonin Syndrome?

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Serotonin syndrome can happen if you have too much serotonin in your body. There have been talks about weed’s role in causing this condition, but is there any truth to it? Can weed cause serotonin syndrome? Here’s what we know. 

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What is Serotonin Syndrome?

Serotonin Syndrome (SS), according to Medline Plus, happens when your body has too much of the hormone serotonin. Even though serotonin is associated with feeling good, serotonin syndrome is a potentially life-threatening condition. 

The primary cause of serotonin syndrome is mixing substances. Medline Plus says, “Serotonin syndrome most often occurs when two or more medicines or drugs that affect the body’s level of serotonin are taken together at the same time. The medicines cause too much serotonin to be released or to remain in the brain area.”

Mixing certain prescriptions together or even prescriptions with recreational substances can cause serotonin syndrome. For example, Medline Plus says that mixing triptans (migraine medication) and certain anti-depressants can cause serotonin symptoms. 

At the same time, using certain antidepressants can cause serotonin syndrome even if you use them alone. Science Direct  says, “Serotonin syndrome is estimated to occur in 14% to 16% of patients who overdose on selective serotonin reuptake inhibitors (SSRIs).”

Signs and symptoms of serotonin syndrome, according to Medline Plus include:

  • Muscle spasms (myoclonus)
  • Tremor
  • Abnormal eye movements called ‘ocular clonus’
  • Fever
  • Agitation

Unfortunately, serotonin syndrome can turn deadly and so you should seek immediate medical attention if you suspect that you have it. 

Can Marijuana Cause Serotonin Syndrome?

There is no evidence that marijuana by itself can cause serotonin syndrome. 

However, too much marijuana usage can present symptoms similar to serotonin syndrome. 

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According to a 2020 scientific journal article, “Since THC may activate serotonin receptors and inhibit serotonin reuptake, its abuse in high concentrations may mimic serotonin syndrome.”

There is actually a case report that sheds light on how using cannabis in high concentration can mimic serotonin syndrome. 

The 2020 article mentioned a 16-year-old teenager who used a dab pen and started to present certain symptoms such as altered mental states. However, the article said, “Lab results were normal with the exception of a drug screen positive for THC. This patient slowly improved over six hours of observation in the ED and was discharged home.” 

Another case study involves a teenager who was misdiagnosed with serotonin syndrome. They were on antidepressants but used a dab pen for three days prior to their hospitalization. The medical professionals determined that they were suffering from cannabis toxicity. 

The case study mentions, “emergency departments have seen a rise in cannabis toxicity that presents with symptoms similar to serotonin syndrome with lower extremity rigidity with hyperreflexia.”

The takeaway here is that dabbing or using dap pens which often have 90% THC can cause negative side effects in some people, especially teenagers. But cannabis is never recommended for teens so this is not surprising. 

Besides cannabis toxicity mimicking symptoms of serotonin syndrome, it is believed by some that mixing cannabis with medication such as antidepressants can cause serotonin syndrome.  

According to Southern California Sunrise Recovery Center, “CBD prevents your body from eliminating the antidepressant as rapidly as it should. As a result, marijuana can raise the amounts of SSRIs in your system.” 

Therefore the risk of serotonin syndrome is increased. 

Can You Smoke Weed on Prozac?

It’s not recommended to smoke weed while using Prozac. As a matter of fact, it’s not recommended to smoke weed with antidepressants in general. 

If you’re unfamiliar, Prozac is the brand name for fluoxetine. It’s an antidepressant classified as a selective serotonin reuptake inhibitor (SSRI).

SSRIs work by increasing the amount of serotonin in your brain by preventing the neurons from not reabsorbing what’s already available. 

According to FHE Rehab, “Doctors aren’t sure why receptors “reuptake” (retain) serotonin in depressed or anxious individuals but suspect it is due to impaired activity within the serotonin pathways in the brain.”

So, are there unpleasant side effects of mixing Prozac and weed? Yes. 

Before we get into them, remember, there are always people who don’t experience the typical side effects of any substance. Therefore, you may have friends who use both and have no side effects but that doesn’t mean there isn’t a possibility for others to have side effects.

That’s why it’s important to discuss combining substances with your doctor because they may be able to assess the possible side effects you may experience based on things like your medical history. 

Okay, back to the possible side effects of using both together. 

Southern California Sunrise Recovery Center mentioned that some people who use SSRIs and weed suffer from bad panic attacks. 

In addition to that, the NHS says that combining Prozac and weed can cause rapid heartbeat and drowsiness. 

Finally, you may be unable to properly assess how well this medication works if you’re still using weed. The Recovery Village says, “You may have symptoms that your doctor attributes to the Prozac when in reality they’re stemming from the marijuana use.”

Can Weed and Prozac Cause Serotonin Syndrome?

Technically it can. 

One reason why it’s not recommended to smoke weed on Prozac is due to the risk of serotonin syndrome. If CBD affects the metabolism of Prozac, then the extra serotonin in the body could very well lead to a serotonin syndrome. 

The Recovery Village says, “In your body, Prozac is primarily broken down by a liver enzyme called CYP2D6. However, CBD interferes with this process so that CYP2D6 cannot break down the Prozac as it normally would. As a result, Prozac levels in your body may increase.”

Can I Smoke Weed While on Zoloft?

It’s not recommended that you smoke weed while on Zoloft. 

If you don’t know, Zoloft is the brand name for sertraline which is a type of antidepressant classified as an SSRI.

Both Prozac and Zoloft are SSRIs. Therefore the effects of mixing Prozac and weed would be similar to mixing Zoloft and weed. 

Therefore, there is an inherent risk of adverse effects when you mix Zoloft and weed, even if you didn’t notice any effects initially. 

Recovery in Tune says, “The initial problematic symptoms related to this combined use may not be easily recognizable, but the risk of adverse effects may increase the longer these two substances are used regularly.”

As a matter of fact, Recovery in Tune says combining both could lead to:

  • Rapid heart rate
  • Panic attacks
  • Difficulty breathing
  • Extreme drowsiness 

Finally, there is a risk of serotonin syndrome because weed may increase the amount of Zoloft and in turn, serotonin in the body. 


Can weed cause serotonin syndrome? It seems so! However, we haven’t found evidence that weed causes serotonin syndrome by itself. At the same time, cannabis toxicity can mimic the symptoms of serotonin syndrome so that’s something to keep in mind. In addition to that, if weed is used with medication that impacts serotonin such as an SSRI, then it could technically cause serotonin syndrome. That’s because weed may interfere with the metabolism of the medication. The bottom line is, be careful if you use extremely high doses of THC and avoid mixing weed with antidepressants.


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].