One thing many people miss about medical research is that most of our medications, procedures, and modes of treatment pass through a rigorous experimental stage. In some cases, the development of a medication or approach to treatment takes years or decades. In others, it may only take months. Almost always, confirming whether a new treatment or approach is valid and beneficial starts in a laboratory, often in a petri dish or a controlled experiment that involves chemicals and chemical reactions only.
After that phase, many potential therapies pass through laboratory testing in animals. If those tests are successful, then the potential therapy or medication or procedure moves to the clinical phase. That’s when researchers conduct carefully controlled trials on humans.
That’s the real proving ground. Not everything that shows potential in a petri dish or in laboratory animals is appropriate for use in humans.
That’s why a new paper published by researchers at the Icahn School of Medicine at Mount Sinai Hospital in New York City got our attention. In the study – “Prefrontal-Habenular Microstructural Impairments in Human Cocaine and Heroin Addiction” – researchers confirmed that an area of the brain associated with heroin and cocaine addiction in animals – the prefrontal cortex-habenula circuit – is also associated with heroin and cocaine addiction in humans.
New Imaging Technology Reveals Connections Related to Cocaine and Heroin Use
Data from the 2021 National Survey on Drug Use and Health (2021 NSDUH) shows the following rates of heroin and cocaine use disorder – what we used to call heroin and cocaine addiction – among adults age 18+ in the U.S.:
In addition, data shows that 5.6 million people over age 18 in the U.S. had an opioid use disorder (OUD) in 2021. That’s why research efforts to identify potential treatment targets for people with substance use disorder are important. Currently, the gold-standard treatment for opioid use disorder is called medication-assisted treatment (MAT). MAT combines traditional therapy, counseling, and social support with medications for opioid use disorder (MOUD), including buprenorphine, methadone, and Naltrexone.
There is currently no known medication approved to treat cocaine use disorder.
With regards to heroin use disorder, MOUDs are effective. In many cases, they not only improve the lives of people with OUD, but save them. However, we use these medications after the fact. Meaning these medications are effective treatments. That’s good.
But they aren’t preventions.
That’s where this research may make an impact. Researchers believe their findings can help identify people at elevated risk of opioid use disorder and cocaine use disorder. They believe their findings can also identify people at increased risk of relapse to heroin or cocaine use disorder. Therefore, this new information may inform not only treatment practices, but also prevention strategies.
Let’s take a look at what they found.
Brain Structures Associated with Cocaine and Heroin Use
In previous studies in animals, researchers confirmed the presence of weak, reduced, and impaired connections between the prefrontal cortex and the habenula – the PFC-Hb circuit – in animals addicted to cocaine and heroin. Or, in science language, they observed that phenomenon in laboratory rodents that acquired self-administration of heroin and cocaine.
In humans, assessing these differences requires specialized imaging technology called diffusion MRI (magnetic resonance imaging) tractography in order to observe the brain in action. This imaging method can identify which circuits are involved in which behaviors, and when they’re involved.
In this preclinical study, researchers found:
- People with cocaine use disorder showed compromised PFC-Hb circuits
- People with heroin use disorder showed compromised PFC-Hb circuits
- Presence of compromised/impaired PFC-Hb connections was associated with earlier onset of drug use in people with cocaine use disorder and heroin use disorder
Interviewed in the online science journal Science Daily, a lead author on the paper observed:
“In addition to identifying microstructural differences…we extended results beyond cocaine to heroin, suggesting that abnormalities in this path may be generalized in addiction. We found that across all addicted individuals, greater impairment was correlated with earlier age of first drug use. This points to a potential ole for this circuit in developmental or premorbid risk factors.”
We’ll discuss these findings below.
How This Research Can Helps Addiction Treatment and Prevention
We mention above that treatment for substance use disorder takes place after the fact, i.e., after a person develops SUD. In most cases, treatment occurs after the person has experienced significant harm as a result of their drug use.
When researchers . In other words, if we know exactly which brain areas may be compromised in people at highest risk of developing a substance use disorder, we may be able to develop therapies to remedy the compromised areas. If they work, we can then reduce or completely prevent the development of a substance use disorder.
That also means we may be able to screen for SUD in the same way we can now screen for risk of other chronic medical conditions. And – if we can develop therapies to address any abnormalities we discover – we can offer preventive, prophylactic care.
Brains scans and targeted neurotherapies may not completely prevent the phenomenon of addiction/disordered use of substances. However, they may help us mitigate the harm caused by substance use. That’s one of our primary goals as providers of evidence-based treatment and support for people diagnosed with substance use disorder.