Washington doctors are sounding alarm on cannabis health effects, survey shows

More than a decade after recreational cannabis was legalized in Washington, a new survey of health care providers suggests many clinicians are concerned about its effects on patients’ mental health.

In a survey of nearly 400 Washington state clinicians, more than half said they are highly concerned about the mental‑health risks associated with cannabis use. Nearly one in five reported seeing patients with cannabis‑related adverse health events as frequently as two to three times per month.

“This is the first time that we actually in Washington State asked clinicians what they are seeing,” lead author Beatriz Carlini, a research associate professor of psychiatry and behavioral sciences at the UW School of Medicine, said.

Researchers reported the findings this week in the Substance Use and Addiction Journal. The 20‑question survey collected responses from 388 doctors, nurses, and other health care professionals between December 2024 and March 2025. Participants were asked about their clinical experiences treating patients with health problems they attributed to cannabis use.

4 conditions, training gaps emerge in cannabis survey

Four conditions emerged most frequently: cannabis hyperemesis syndrome — severe, repeated vomiting — reported by 70% of clinicians; cannabis-use disorder, at 65%; anxiety, at 63%; and psychoses or hallucinations, at 53%. More than a third called psychosis the most serious adverse event they encountered.

The survey revealed significant gaps in training. Nearly 66% of respondents reported little or no knowledge of how cannabis interacts with other medications. More than 42% said they had a limited understanding of cannabis-induced psychosis. And nearly 75% said they want more training on how to screen for cannabis use and manage related health risks.

“They are reporting being concerned. They are reporting being not educated enough to proficiently take care of the situation,” Carlini said. “We need more specific training for clinicians in our state.”

More than 80% said they would be more likely to intervene if they had established treatment protocols and better referral options.

“Cannabis was treated as a secondary, relatively benign substance for such a long time,” Carlini said. “There are no facilities, treatments, or resources specific to cannabis.”

Today’s cannabis far more potent than what voters legalized in 2012

Carlini noted that today’s cannabis products bear little resemblance to what was on the market when voters legalized the drug in 2012. Washington does not cap THC concentration in flower or concentrates. The average THC level for flower was 21% in 2022, with concentrates averaging 69%, according to the Washington State Liquor and Cannabis Board.

“Before legalization, it was a way milder substance,” Carlini said. “Now the manufacturing has become extremely concentrated, so this has been causing more problems.”

The Washington CannaBusiness Association, a trade group representing licensed operators, said the study does not distinguish between harm from regulated products and harm from the illicit market.

“The THC content on regulated products is required on the label, and each product is subject to rigorous testing standards that are nonexistent in the illicit marketplace,” the association said in a statement.

The group pointed to a 95% compliance rate among licensed retailers for restricting sales to customers 21 and older, and said it supports enforcement against unlicensed sellers rather than prohibition-based approaches.

Carlini said she is not calling for an end to legalization but is advocating for potency regulation. She co-authored a 2022 report for the state Legislature with policy recommendations on THC limits, but none were adopted.

“You actually need to make cannabis more similar to the cannabis we had in the past that we originally legalized,” Carlini said.

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