DENVER—A recent spousal murder case is the second death this year linked to edible marijuana, sparking questions and concern about what role, if any, the drug played.
Last month, a 19-year-old student fell to his death from a hotel balcony after eating six servings of a pot cookie.
"There's just not enough information right now to say, absolutely, pot was to blame," 9NEWS psychologist Max Wachtel said.
In the case of the murder, there are other factors to consider besides pot.
Police say suspected shooter Richard Kirk was also on medication for back pain in that case, so pot may not have been the only thing in his blood.
Sources told 9NEWS Kris Kirk was on the phone with 911 for approximately 12 minutes before her husband Richard allegedly shot her in the head while she was still on the line.
Court documents revealed that Kirk could be heard in the background of the call "talking about some marijuana 'candy' that he had got from a store."
"There's certainly an extreme likelihood that [marijuana] contributed," Wachtel said. "What we know about the case at this point is that he probably ingested an edible, had way too much pot in his system."
That can cause problems, says Wachtel, who points to a study that looked at the brain on THC, the psychoactive drug in pot.
It found that part of the brain called the prefrontal cortex, gets more active when exposed to the drug. This area is believed to bring in sights and sounds from the world around you, so more activity could mean more sensations.
However, THC also caused another part of the brain called the striatum to slow down.
Scientists think that brain region helps you deal with all those sensations coming in, so less activity could mean a tougher time making sense of the world.
In extreme cases, it can cause a type of psychosis similar to schizophrenia, says Wachtel.
"Little things become huge," Wachtel said. "So a touch on the skin or a little sound that you hear off in the corner becomes a monster or becomes somebody telling you to kill somebody else."
ER doctors say that's rare to see with pot. Usually people come in very sedated.
Regardless, marijuana supporters concede it's easy to overdo it with edibles.
People think, "'Oh, I smoke cannabis, I'm fine,'" said Genifer Murray who runs a marijuana testing company called CannLabs. "Absolutely not, you should always start with 10 milligrams."
10 milligrams is the state's definition of a dose of edible THC.
Karma Kandy, the edible product police say murder suspect Richard Kirk bought, is sold with more than 100 milligrams in as single piece of candy.
There are similar facts in the case of the 19-year-old who jumped from the hotel. Police say he ate one cookie that was 6.5 doses.
A smaller bite didn't produce a high right away, so he ate the whole thing, according to statements in the police report from those who were with him.
It takes longer to get high eating pot than smoking it and the effects can last for hours.
"15 to 20 years from now I think we will look back and be shocked that edibles were legal," Wachtel said. "I think they are not going to withstand public scrutiny. I think that bad stuff is going to continue to happen."
"I think that's ridiculous," countered Murray. "A lot of people don't smoke, so you always want to give them another option."
Murray suggests that people who use edibles, especially for the first time, find products that are already divided into 10 milligrams servings of THC, so they don't have to break off pieces of a cookie or brownie.
All sides seem to agree more scientific study of marijuana's effects in different forms could be useful.
There's no rule against having a single piece of candy that contains the maximum 100 milligrams of THC for an edible item sold as recreational pot.
Colorado has no limit at all on THC content for medical marijuana edibles.
The THC content listed on edibles isn't always trustworthy, either.
Mandatory THC potency testing won't be required until May under state rules. In the meantime, untested products are required to come with a disclosure to the buyer saying they have not been tested.
