NORMAN, Oklahoma - An addiction researcher testified in defense of Johnson & Johnson on day 29 of Oklahoma's opioid trial.

He said addiction rates aren't nearly as high as the state of Oklahoma's witnesses made them out to be.

Dr. Richard Delagarza told the judge he's an "addiction neuropharmacologist," which means he researches how different drugs effect people's brains.

Delagarza spent the day trying to disprove the different witnesses and studies the state of Oklahoma used to prove their case.     

The state's witnesses talked about how opioids aren't safe for every day use, and are highly addictive, but Delagarza said that's not necessarily the case.             

He cited some studies that said fentanyl patches, like Johnson & Johnson's Duragesic, are safe and effective ways to treat pain.             

He also disagreed with the state's argument that opioid addiction is an incurable disease that people live with the rest of their lives.

"The brain can recover if it's given the chance," Delagarza said. "If individuals stop using the drugs, you can see some recovery of function."

The state's attorneys argued Delagarza isn't a qualified witness.

State Prosecutor Reggie Whitten asked why Delagarza hadn't talked about any studies he actually performed himself.

"That's kind of what you've done in this courtroom," Whitten said. "You've read all these articles, people who have not come down here to testify. You come into this court, you give the judge a sort of a book review, or a movie review like Rotten Tomatoes. Fair enough?"

"Well, my attempt was really just to explain the science to the judge," Delagarza said. "It's not a matter of being a book reviewer. It's a matter of having 15 to 20 years in the field."

Whitten also pointed out that Delagarza is not a medical doctor, unlike the state's witnesses who Delagarza directly challenged today.

"Unlike many of the authors of the medical articles and the medical studies that you've told Judge Balkman about today for hours and hours, you are not an MD, a medical doctor, right?" Whitten asked.

"I am not an MD," Delagarza said.

Delagarza told the judge he's spent more than 15 years writing and publishing articles about different drugs, as well as performing human clinical trials for different drugs.