Medical marijuana use has been legalized in 23 states and the District of Columbia, prompting some pro-pot voices to predict their battle is almost done. Nearly half a dozen more states may vote on the issue in 2016, making legalized cannabis nearly coast-to-coast a real possibility.

But legalization is just one step to reaching many medical marijuana proponents' goal: another treatment option. And safety regulations have lagged far behind the drug's state-to-state progression, leaving many patients to wrestle with questions about usage and side effects. These are issues Americans usually expect pharmacies, manufacturers, and government regulators to have answered before a legal product is sold, including how much to take, when, and how.

Mostly these are questions of science, but also trust. "Patients are really trying to figure out where I can get the most accurate information," Dr. Scott Novak, a senior developmental epidemiologist at nonprofit research institute RTI International, told reporters in a Thursday briefing.

Problems with consistency, quality control, and consumer safety are bound to arise in such a quickly-growing and little-regulated field, researchers say, causing many patients to accidentally overdose. While marijuana overdoses are almost never fatal, an array of possible side effects, from nausea to hallucinations, can land patients in hospitals, where not all staff are prepared to recognize or properly treat them.

More than 65 percent of medical cannabis users have experienced an overdose, which suggests they're struggling with "trial and error" self-treatment, Dr. Novak says.

The confusion is understandable: there's little scientific or industry agreement on even the most basic questions, such as the correct size of a dose, and the plethora of new products springing up to meet legalized markets has created more misunderstandings. Labels recommended doses range from 1 or 2 milligrams of tetrahydrocannabinol (THC), the chemical responsible for most of marijuana's effects, to over 1,000.

Prof. Ryan Vandrey of the Johns Hopkins School of Medicine says his research has found that the majority of edible cannabis products, a growing trend, had their THC dosage mislabelled by more than 10 percent in California and Washington.

Part of the research gap simply comes from marijuana's changing legal status. At the federal level, it is still outlawed as a Schedule I substance. However, the Obama administration has recommended that federal prosecutors not prosecute medical marijuana manufacturers. And regulations at the state level are just that – state-to-state – causing confusion when users travel or move.

"We have an industry that’s been illegal for so many years that there’s no research," Frank Conrad, director of the Green Lab in Denver, Colo., told The Associated Press. "There’s no guidelines. There’s nothing."

But as some patients turn to marijuana to try to alleviate their symptoms, it becomes all the more urgent to set industry standards. Finding reliable information and products from state to state can be particularly challenging for first-time users. "You may be a little sheepish as you go into the dispensary," and reluctant to ask for help, says Novak. Up to one-quarter of authorized medical marijuana users don't even tell their primary doctor they're using pot, making it less likely they'll find good guidance.

Industry officials say they're eager for guidelines, however, and there's "more of an effort to get industry stakeholders together," according to Dr. Brian Thomas, a principal scientist in RTI's Analytical Chemistry and Pharmaceutics division. Washington state, for example, now requires thoroughly labelling all cannabis products in-state and requires quality assurance tests, whose results must be available for customers. In Colorado, packaging must disclose any pesticides or herbicides used in production.

Many growers and dispensary staff are motivated to help customers' address health care issues, and streamlining recommendations for sellers and buyers alike could help.

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"These people are not criminals," Michael Minardi, a lawyer who is pushing for Florida to legalize the drug, told local NPR station WUFT. "They are just trying to stop the suffering and progression of their diseases."

Editor's Note: The original version of this story misspelled the name of RTI's Dr. Scott Novak.