ST. LOUIS — Medical marijuana sales in Missouri won't likely begin until the second half of 2020, but the state health department has already approved more than 35,000 patients who want to use the drug, far exceeding projections.

Lyndall Fraker, director of medical marijuana for the Missouri Department of Health and Senior Services, said Monday that psychological disorders were the No. 1 reason for patient requests, followed by chronic medical conditions.

The 35,532 approved applicants are far more than projected by researchers with the University of Missouri's Economic and Policy Analysis Research Center for this early in the process.

Only 1,090 applications have been denied, according to data Fraker presented.

Nearly two-thirds of Missouri voters in November 2018 approved legalizing medical marijuana. The drug must first be grown at approved sites and tested, so sales aren't expected to begin until late summer at the earliest.

"We want to make sure that all Missourians feel good about our program, that it's safe, regulated," Fraker told several hundred people gathered at a medical marijuana convention in St. Louis.

Less packed than at last year's inaugural Missouri marijuana-industry conference, the hotel ballroom included a few hundred people, dozens of them tied to companies that won coveted permits to run cannabis-related businesses like dispensaries and commercial grow operations.

A representative with Midwest Canna Expos, the conference organizer, said the company did not have an attendee count by late morning Monday because many attendees registered at the door, not in advance. As she introduced Fraker, Midwest Canna Expos CEO Karin Chester told the crowd that 129 vendors were attending Missouri's biggest weed-industry event this year.

The health department awarded licenses in December and January — 60 licenses to growers, 86 to manufacturers and 192 for dispensaries. The awards left hundreds of applicants disappointed. The state's Administrative Hearing Commission said it has received 845 appeals filed by companies that were denied state marijuana licenses.

The intense competition for licenses is understandable since authorities project that Missouri's marijuana industry will exceed $100 million in sales by 2025. Meanwhile, proponents have launched a petition drive aimed at letting voters decide in November if recreational marijuana should be legalized in the state.

Clovr, a Kansas City manufacturing company, was among dozens of businesses with booths at the show. It was also among the license recipients.

CEO Josh Mitchem, 40, said he's eager to see Missourians benefit from medical marijuana as they have in Colorado, where he also had a business.

"It's exciting because we've seen the impact it means for patients," Mitchem said. "We know the naysayers say it doesn't cure anything, but it improves patients' quality of life."

Likely for the first time, Fraker publicly presented a county-by-county map of the Show-Me State indicating the places where marijuana patients live. St. Louis County and Kansas City lead the pack, with Springfield next, followed by suburban St. Louis counties and Columbia.

In rural areas, the I-44 and I-70 corridors stood out as relatively patient-heavy, along with the Joplin and Branson areas. Very small numbers of patients are located in regions including the Missouri Bootheel and northern Missouri areas abutting Iowa.

Fraker also presented data on the ages groups of cannabis patients.

He said the portion of patients in their 60s, 16.67 percent, so far "is actually much higher than I would have guessed that it might be."

People in their thirties make up the largest single group, 21.7 percent of the patient count, followed by slightly smaller percentages for 50- and 40-somethings.

Twenty-somethings are a relatively smaller group: 12.35 percent of the total.

"We might have thought the 18-to-29-year-old bracket would have been the highest, or maybe a little higher," Fraker observed.

Specific details about how the program will work are still subject to change by the Legislature, raising concerns among leaders of the Missouri Medical Cannabis Trade Association. The House has approved requiring an in-person doctor appointment for those seeking a medical marijuana ID card, rather than a consultation via phone or the internet. Another proposal would prohibit marijuana-infused edibles.

Jack Cardetti, spokesman for the trade association, said many doctors recommend edibles. He also was critical of another bill that would allow people to be fired if they simply obtain a medical marijuana card.

"We shouldn't be making patients make a choice between their medicine and their jobs," Cardetti said.

The Associated Press and Gregory J. Holman of the Springfield News-Leader contributed to this report.