She stabbed a man 108 times and got probation. What to know about 'cannabis-induced psychosis.'

The recent sentencing of Bryn Spejcher, the 33-year-old who stabbed a man she was dating more than 100 times during a cannabis-induced psychotic episode, has brought national attention to what experts call a rare yet increasingly common side effect of recreational marijuana use.

Spejcher, who was a novice marijuana user, was smoking from 26-year-old Chad O’Melia’s bong in 2018 when she went into a coughing fit and began to hallucinate. She said she thought she was dead and heard voices of paramedics trying to save her; the voices then said she had to kill O’Melia to bring herself back to life.

Spejcher stabbed him with two large knives 108 times before stabbing herself in the neck. Blood tests found no other intoxicating substances in her system aside from THC, the psychoactive compound in cannabis, and she had no prior history of mental illness, violence or suicidal impulses.

Evidence of cannabis-induced psychosis was so clear that the prosecution’s medical expert agreed with the defense’s experts about Spejcher’s fit, which led her murder charge to be reduced to involuntary manslaughter. Last week, she was sentenced to two years probation (meaning no prison time) and a 100 hours of community service focused on raising awareness about the effects of cannabis-induced psychosis.

Experts say that they have treated an influx of people with cannabis-induced psychosis in recent years, particularly teens and young adults. They blame an increasingly competitive market that has prompted sellers to make their products more potent, in part due to wider access to the drug as it becomes legally available in more states.

“Fortunately, these kinds of terrible outcomes like this case don't happen very often, but we’re seeing more of it over time,” said Dr. Tony George, a senior scientist with the Centre for Addiction and Mental Health and a psychiatry professor at the University of Toronto’s Temerty Faculty of Medicine. “This is not going away anytime soon. All we can do is ring the alarm bells.”

What is cannabis-induced psychosis?

Cannabis-induced psychotic disorder is psychosis triggered within minutes, hours or days of smoking or consuming marijuana. The disorder is listed in the DSM-5, a catalog of mental disorders that health professionals use to diagnose patients.

Psychosis is a collection of symptoms that make it hard to distinguish between what’s real and fake, a “disconnection from reality,” according to Dr. Sharon Levy, chief of the addiction medicine division at Boston Children’s Hospital.

Psychosis is most often associated with schizophrenia, bipolar disorder and severe depression, but sleep deprivation and prescription medications, as well as alcohol and drugs such cocaine, ecstasy, LSD, amphetamines and cannabis, can cause psychosis, the National Institute of Mental Health says.

The most common symptoms of psychosis, regardless of cause, are delusions (false beliefs) and hallucinations (seeing or hearing things that aren’t there). Others include paranoia, confused speech, lack of motivation, anxiety, sleep disruption and unusual or overly intense ideas. Although some psychotic symptoms overlap with those of being “high,” Levy said it’s important to focus on their magnitude to differentiate them from a typical drug-induced experience.

Most people who have a cannabis-induced psychotic episode rarely become violent, “but their behavior does become unpredictable because they’re responding to internal stimuli that people around them aren’t aware of,” Levy said. “That’s where it can get dangerous because you can’t predict what someone will do next.”

Kris Mohandie, a clinical and forensic psychologist, and a frequent consultant to law enforcement agencies, who examined Specjher for the prosecution, testified that he has consulted on “at least half a dozen cases throughout the years” of violent episodes that may have been triggered by cannabis-induced psychosis.

Other drugs like cocaine or crystal meth are more likely to cause violent psychotic behavior, George said.

What increases risks of cannabis-induced psychosis?

The more often you smoke or consume cannabis, the greater amount you use and the higher the potency of the products involved will increase your risk of cannabis-induced psychosis, according to research.

A 2019 study published in The Lancet Psychiatry found that the odds of psychosis among adult, daily cannabis users were 3.2 times higher than for those who had never used the drug, and nearly 5 times higher for those who used high-potency cannabis every day.

The age a person starts to use cannabis matters too. Research has found that people who begin using the drug at age 15 or younger have greater chances of developing psychosis and of developing it earlier than people who start later in life.

The average THC content in confiscated marijuana samples in the early '90s was less than 4%. Today it can surpass 15%, George said, meaning smaller amounts of marijuana now carry higher risks of these outcomes.

A family history of psychosis is another major risk factor for disorder, George said.

Cannabis-induced psychosis isn’t a one-and-done situation

Experiencing any kind of drug-induced psychosis increases your risk of developing a chronic and severe mental illness, such as schizophrenia and bipolar disorder.

Levy said that THC “temporarily poisons the neural circuits in the brain that help people distinguish between things happening on the inside and outside.” That's why it’s common to experience both euphoria and paranoia while high on marijuana until THC is metabolized in the body. “But in those who may be genetically or environmentally predisposed, are using very potent weed, or whatever the magic combination is, their circuits are too injured to recover,” which can increase their odds of developing a psychotic disorder.

The data are concerning, experts say, and something we need to be aware of as marijuana use increases in the U.S.

“When we think about regulating cannabis, we need to have these numbers in the back of our mind,” Levy said. “These experiences are probably very common, we just don’t surveil for them. And based on what [studies] tell us, there’s a lot on the line here.”

Tony Biasotti contributed to this report.

This article originally appeared on USA TODAY: What is cannabis-induced psychosis? California stabbing explained