Experiments and Breakthroughs that Changed How We Understand Substance Use Disorder

Season 5 of Lost Women of Science tells the story of Marie Nyswander, and how she revolutionized heroin addiction treatment. We’re very excited to share our BONUS EPISODE with you this Thursday, June 1st.

When Marie began working with people addicted to opiates, addiction itself was poorly understood. Her early success with methadone treatment cast doubt on the idea that addiction was a moral problem, and reframed it as a disease in the body, like any other.

To this day, addiction continues to be studied and rethought, with increasingly nuanced conclusions. It’s a vast topic, and we couldn’t cover everything in the season, so in this newsletter we’ll discuss some of the most significant findings, and the people who uncovered them.

The early attitude on drug addiction was that it was a hopeless, often fatal ailment, and that people with substance use disorder were bound to descend deeper and deeper into their addictions.

But Canadian psychologist Bruce K. Alexander of Simon Fraser University wasn’t convinced of this. The evidence that addiction inevitably destroyed lives came partially from what Alexander believed was a very limited study, in which researchers confined rats to tiny cages and gave them two options: water or heroin. Overwhelmingly, the rats chose hits of heroin, over and over again – until they overdosed.

All the rats in the study were living in solitary confinement. Alexander wondered if the results would be different if they lived in better conditions. Enter: Rat Park.

In the late 1970s, Alexander constructed a haven for his test subjects. It was 200 times the size of a standard laboratory enclosure, included hamster wheels and other play spaces, and housed a community of 16-20 rats. His conclusions matched his hypothesis: With emotional and physical wellness, the rats were much less inclined to use the opioid lever. Some occasionally chose to use the substance, but did not seem to become addicted. None overdosed.

In another trial, Alexander put the rats in solitary confinement and gave them opioids for a prolonged time, enough to get them addicted. When he introduced the addicted rats to Rat Park, he found that they engaged with the other stimuli surrounding them and began opting for water instead of opioids. The rats seemed to undergo withdrawals voluntarily when presented with alternative stimuli.

Alexander’s results represented a breakthrough in addiction treatment. The factors that caused addiction and prolonged drug use proved to be more complex and environmental, inviting new theories on and possible treatments for substance use disorder (SUD).

Addiction and the Brain

Another scientist who transformed the way society views addiction is Dr. Nora Volkow, the Director of the National Institute on Drug Abuse (NIDA).

Before her work, most researchers believed that addiction craving stemmed from a part of the brain associated with impulsive behavioral responses, called the limbic system. In the 1990s, as Volkow reviewed PET scans of men addicted to cocaine, she had a breakthrough. Volkow realized brain scans could show that a person was addicted to opioids—and the tell wasn’t in the limbic system. It was in an area of the brain associated with decision making and moderating social behavior: the prefrontal cortex.

“No one at that time thought the frontal cortex was important in addiction—nobody!” Volkow said in a 2015 interview with Brain & Behavior. Her breakthrough allowed researchers to shift their focus on addiction research to a different part of the brain.

Volkow’s discovery emphasized that opioid addiction involves a biological process that inhibits self-control. Like Alexander’s Rat Park study, Volkow’s findings made room for a more expansive view of addiction that shifted the focus away from morality.

A New Frontier for Medication Treatment

Marie Nyswander’s greatest contribution to addiction research was the idea that SUD could be treated with another opioid, methadone. Now, some researchers believe they might be able to treat SUD with psychedelics.

Last April, three psychologists and a neuroscientist—Grant Jones, Joshua Lipson, Matthew K. Nock, and Jocelyn A. Ricard—found an association between reduced risk for opioid use disorder and the substance that makes ‘magic mushrooms’ psychoactive. The substance, psilocybin, may eventually become a treatment option for people navigating SUD recovery.

As author Michael Pollan explained in 2018 to Time Magazine on the power of psilocybin: “All those deep grooves that lock us into patterns of both thought and behavior are dissolved and temporarily suspended in a way that allows us to break those patterns.” This could hold true for when the pattern is drug addiction.

Though the psilocybin study was merely correlational, researchers have found other therapeutic uses for psilocybin, including treatment for depression, anxiety, eating disorders, and chronic pain.