CLEVELAND — Deputy Cody Karena is a drug recognition expert, or DRE, at the Monroe County Sheriff’s office in Michigan.


What You Need To Know

  • Unlike alcohol, there isn't a device that quickly detects impairment for marijuana. 

  • Law enforcement rely on the training of Drug Recognition Experts, or DREs.

  • A prosecutor believes Ohio may need more DREs now that recreational marijuana is legal. 

He’s trained to detect impairment for marijuana and a number of other drugs. He’s been busier than ever since Michigan legalized recreational marijuana in 2018.

“It’s called lack of convergence,” Karena said, while demonstrating an impairment test. “So I’m seeing if their eyes can converge on a stimulus.”

He has several tests specifically for marijuana and has undergone special training to get certified as a DRE. He said filling out a DRE report takes much longer than a normal incident report.

“DRE school is the hardest training I’ve ever done,” Karena said. “I mean even…. I was ten years in the military, it’s still the hardest training I’ve ever done. I mean the final exam I was doing it for eight hours. I know one guy, it took 13 hours.”

Greg Gentile is an attorney who’s prosecuted cases with the help of a DRE and has defended clients against a DRE. He said Ohio will probably need more DREs since recreational marijuana is legal.

“Once the availability of marijuana becomes as prevalent as we all expect it to be,” Gentile said, “we’re going to need more DREs and police officers that are certainly better trained on how to detect and arrest impaired drivers on drugs.”

Gentile said as a prosecutor, DREs can be reliable since they usually have to be right, so he likes them to back up their assessment with an actual blood test. He said being wrong could hurt their case.

“Then the results come back and the officer finds out was a right or was I wrong,” Gentile said. “If the officer was wrong. That’s gonna hurt in court because obviously how valuable, how much credibility does an officer have for determining what classification of drug somebody’s impaired on when they’re wrong.”

Deputy Karena is the only DRE in his county. He said the testing is vital, since there isn’t a device that can detect impairment for marijuana.

“We take our 12-step systematic and standardized process and we can take those individual observations that might be subjective to somebody, but we can actually make them objective,” Karena said. 

Karena likes to back up his claim of impairment with a blood test. 

“If we’re seeing something that’s consistent with impairment but then nothing comes back in the blood,” Karena said. “Is that because it’s a drug that’s not tested for? Or is it because maybe they had some kind of medical impairment going on? And then that’s where we have to go back to our evaluation and see what exactly happened.”

Karena said it’s best to test someone early on, because impairment can wear out, and blood tests can take months to get results.