JACKSONVILLE, Fla. -

Synthetic marijuana is illegal in Florida, but that's not stopping it from popping up in local stores.

Clay County deputies have seized the drugs from three stores just this year.

An Orange Park psychiatrist is now speaking out about the potential effects of synthetic marijuana and the surprising number of teens he's treating.

Dr. Marcus De Carvalho said about 15 percent of the patients he sees a week have used synthetic marijuana, and most of them are teens. The results of using the drug, he said, can be severe.

"Hallucinations that can be command-like, meaning telling you to kill yourself, kill other people," De Carvalho said. "So it's very serious."

As a result, he decided to write a blog and a letter to other doctors and people in the community to let them know what's going on.

"I just started to become really concerned with the majority of the patients I was seeing in my private office," De Carvalho said. "They'll come in with complaints of psychosis, antidote, hallucinations, paranoia, even visual hallucinations."

Synthetic marijuana is made of natural herbs, then sprayed with synthetic chemicals that mimic the effects of marijuana when consumed.

De Carvalho says he always asks patients if they use marijuana. In one teen, like many others, this was the response.

"Clearly, she was like, 'No, no, no, I've never tried it, but I have tried some of the over-the-counter light marijuanas that are really light that really don't have that effect, and that really scared me,'" De Carvalho said.

He said that's the issue: Teens believe synthetic marijuana is safe. But De Carvalho said it can be more dangerous than marijuana itself.

"That over-the-counter marijuana, that K2 spice or mojo or bath salts actually bind the receptors in the brain that marijuana binds 100 times tighter," De Carvalho said.

He said that can actually change the shape of the brain and leave long-lasting psychological effects. De Decavallo said that's why it's important for parents to be on the lookout for the drugs.

"You raise your child and you want your child to function in a society normal as a good citizen, as a good adult," he said. "When they use these drugs, I mean, it kills their chance."

De Carvalho offers this advice to parents: Get educated, talk to other parents, be open and take it as it goes, don't be surprised, be flexible, do whatever possible to make it stop.

How do you treat people after they use Synthetic Marijuana

Those who use synthetic marijuana should be treated like anyone who has been diagnosed with a psychotic illness, De Carvalho said. He said that means medication, but right now there is no specific medication for people who have used the drug.