PEORIA — As someone who knows what it’s like to suffer from substance use disorder, Sam Snodgrass is on a mission to help people understand.

At the drug abuse treatment clinic in Little Rock, Ark., where he works, Snodgrass helps his clients understand their condition. In his role on the board of directors for Broken No More, a group working to effect policy change in the failed war on drugs, Snodgrass is working to help lawmakers understand. And, when he comes to the Peoria riverfront to speak during the Stop the Stigma, Central Illinois Overdose Awareness Walk on Aug. 19, he hopes to help loved ones understand — opioids literally change the brains of people who abuse them.

For Snodgrass, the mission is deeply personal — understanding the changes helped him stop using opioids after a devastating 22-year journey in which he hit rock bottom again and again.

The revelation happened in the winter of 2012 in the library at the University of Arkansas for Medical Sciences, where, years before, Snodgrass had completed a postdoctoral fellowship and became a faculty member and researcher. It was much more than an ah-hah moment, Snodgrass said.

“It was like sliding 1,000 keys into 1,000 doors and they all opened at once. It was just a huge revelation to me. It gave me the understanding of why I couldn’t stop.”

In the early stages of his sobriety, Snodgrass began venturing into the library to delve back into his chosen field of study, the brain.

“I started reading about neuroscience, and what they had discovered about the brain with CAT scans and MRIs,” said Snodgrass. “I kept reading and it finally clicked in my brain why I couldn’t stop using opioids — over time, with escalating doses, you actually change the molecular structure of the brain.”

Snodgrass first tried opioids in 1976, when he was 20, and for the next 13 years he was a casual user. Then he began a fellowship in the pharmacology and toxicology department at the University of Arkansas for Medical Sciences to study how drugs affect the brain and behavior. While most of the drugs were locked up, a big bottle of methadone lay forgotten in a drawer. It gave Snodgrass the opportunity to imbibe frequently.

“I started shooting it every day, then two to three times every day,” he said. “As I escalated my dose, the whole time I was doing it, I thought I could stop. I believed that right up until the time I couldn’t stop.”

Why he couldn’t stop was a mystery to Snodgrass.

“I’d say ‘I’m not gonna do it today,’ and then go out and do it. It was something I couldn’t understand.”

Snodgrass eventually lost his job at the university. Though he went on to teach elsewhere, he continued to struggle with substance use disorder. By 2008, he was unemployed and homeless.

“I was 52. I had lost everything. I was sleeping in homeless shelters, people’s floors, on the ground, and still hustling to find ways to get the money to buy what I needed to make it through the day to end the starvation.”

Though Snodgrass was undoubtedly hungry for food, the starvation he describes was for drugs. Drugs had become far more important to him than food.

When Snodgrass unlocked the door of understanding, he realized why he experienced that overwhelming craving.

“We are born with an endogenous opioids system in our brains,” Snodgrass said.

Our brains naturally produce opioids, or endorphins, feel-good chemicals that help fuel the activity of the day.

“When you take a dose of heroin, it floods the brain with far more opioids than the body can produce on its own,” said Snodgrass.

Eventually, with continued use of opioids, the brain quits producing endorphins, at which point the user will be forced to continue using the drugs to replace what’s missing.

“We get to the point where we have shut our endogenous opioid system down, and if we don’t have opioids in our brain, we starve for them. The craving is a real starvation,” Snodgrass said.

To make matters worse, users develop tolerance for the drugs, and require higher doses to achieve normalcy.

“When we first start using we have options  — we have jobs,” he said. “As our tolerance rises, we end up spending $250 a day just to be able to function. When you spend that kind of money you end up out of options quick.”

Opioid addicts starve for drugs two to three times a day. It’s a desperation that makes people do things they would have never done before they started using.

“We’re not bad people, but we are doing things that are not us,” he explained. “We don’t take our grandfather’s shotgun and hock it to go do drugs, we take it and hock it so we can stop starving — there’s a difference. This is what families don’t understand, and we can’t explain.”

Understanding in users, families, and society is key to combating the opioid epidemic. For Snodgrass, the understanding helped him achieve sobriety for more than six years.

“It helped me to understand why I couldn’t stop. It helped me to understand that I could never use again. It helped me to understand that this is a disease I don’t control. I cannot tell you that I won’t use again next week, next month, next year. I don’t control it. It can come back like any other chronic condition. I am in remission.”

Though Snodgrass did not use replacement therapies to manage his addiction, he says methadone and buprenorphine are powerful drugs that help many people get their lives back.

“I’m actually not using them, which makes me kind of an idiot. It puts me out there every day where I can screw up,” he said.

Used correctly, methadone is a medicine that can help people with the chronic disease of substance use disorder lead healthy lives.

“People don’t understand that it’s just like taking medication for any chronic disease,” he said.

It’s a long-term thing, because opioid use literally alters the brain, he said.

“You change the brain forever.”

Leslie Renken can be reached at 686-3250 or lrenken@pjstar.com. Follow her on Twitter.com/LeslieRenken, and subscribe to her on Facebook.com/leslie.renken.