Just over half of the 55 dispensary staff members surveyed in a new, small study had received any sort of formal training for their current positions.

Only 20 percent had received medical training on the health effects of marijuana, and just 13 percent received training on the science of the drug, the researchers found. The staff members surveyed worked at medical or non-medical marijuana dispensaries in Colorado, California, Arizona, Oregon, the District of Columbia, Connecticut, Rhode Island, Massachusetts and Maine.

Some of the dispensary staff members in the study made recommendations to people who were purchasing marijuana that were not accurate or appropriate for treating their customers' conditions, said lead study author Nancy Haug, a professor of addiction medicine at Palo Alto University in California.

For example, 13 percent of the staff members in the study said they had recommended types of marijuana that are high in levels of THC — marijuana's main psychoactive component — to patients who intended to use the marijuana to treat anxiety, the researchers found. However, previous research has shown that THC may make anxiety worse, Haug told Live Science.

And 7 percent of the staff members recommended THC for treating epilepsy, yet research has shown that another marijuana compound, called CBD, may be effective for for treating epilepsy, Haug said.

The researchers found that 35 percent of the dispensary staff members had received customer service training; 26 percent had received business training; 20 percent, medical training; and 13 percent, scientific training. Twenty percent received other training related to learning about cannabis.

Yet 94 percent of the study participants said that they had provided advice to customers. That included recommending which marijuana strains customers should use and advising customers on the benefits of marijuana for particular symptoms.

The staff members in the study said that the most common symptoms reported by their customers were chronic pain, insomnia and anxiety. Of all staff members in the study, 62 percent said that they always or often checked in or followed up with their customers after their purchases, to ask about their health conditions, according to the study, published Dec. 1 in the journal Cannabis and Cannabinoid Research.

Overall, the staff members were more likely to recommend marijuana with an equal ratio of THC to CBD for people with anxiety, PTSD or trauma and Crohn's disease, rather than recommending marijuana that's high in THC, the researchers found. This is in line with what experts recommend, the researchers said.

Staff members were also more likely to recommend marijuana with high levels of CBD and equal ratios of CBD to THC for customers with ALS, epilepsy and muscle spasms, rather than recommending marijuana high in THC. For people with epilepsy and the other conditions, this recommendation is also in line with research suggesting that CBD may benefit patients.

However, some staff members made recommendations that went against current recommendations for a given condition, the researchers said. For example, 10 percent of staff members said they recommended marijuana with high levels of CBD for people who wanted to increase their appetite, but research shows that THC, not CBD, may benefit appetite, the researchers said.

The results, Haug said, show that dispensaries should provide more training based on findings from current scientific literature on cannabis.