A recent post here reported how two University of Maryland Brain and Behavior Institute researchers received a grant to study opioid use disorder (OUD) relapse, as it relates to genetic and epigenetic behavior. One of those experts is part of the biology department, while the other hails from the psychology department. Together, their ambition is to “map the neural circuits that trigger relapse.”

By analyzing tissue extracted from addicted rats, and utilizing next-level computational methods to crunch genetic and epigenetic data, they intend and expect to eventually gain the ability to “identify which genes are turned on or off in response to addiction-related signals.”

This is huge, because some people are born with a predisposition toward reward deficiency syndrome (RDS), which constitutes a pretty strong indication that they will, at some point, develop what is known as an addiction. Moreover, this is equally true of dependency on a substance or on a behavior. That factor alone goes some way toward settling the debate over whether overeating that leads to obesity is a “substance addiction” or a “behavioral addiction.” In this conceptual framework, it is a distinction without a difference, and basically doesn’t matter.

For Psychology Today, Marc Lewis, Ph.D., reported on the thought processes of Kenneth Blum, who originated the term “reward deficiency syndrome.” A person tends to do (and over-do) whatever makes their brain light up, igniting “dopamine circuits in the nucleus accumbens and its neighbors in the prefrontal cortex and motor system.”

Many dopamine receptors are involved, principally the D2 receptor, which influences attention, motivation, motor control, and other human attributes. But what if there are not enough D2 receptors? Or too many of them? Well, there are reasons why Lewis calls the receptor “a gateway to the underworld of the psyche.” We’re talking about schizophrenia, attention deficit hyperactivity disorder, obsessive-compulsive disorder, and more — including every type and variety of addiction.

While a fetus is developing, the DRD2 gene might vary by having an allele that causes a shortage of D2 receptors. This is related to the statistical indications hinting that addiction is heritable. Lewis says,

There’s lots of evidence that addiction runs in families… Blum cites some pretty convincing research showing that addictions shared across generations […] correspond with this nasty dopamine allele. In other words, the allele gets passed down to the same offspring who end up becoming addicts.

What happens where there is a shortage of D2 receptors? Often, not much. The person has flat affect, doesn’t get excited about things, and derives little enjoyment from life. It’s reward deficiency syndrome, which compellingly calls for the use of alcohol, drugs, gambling, or some other thrill-seeking behavior, just so the person can feel alive. The bottom line or “takeaway” here is that “reward deficiency leads you to seek out the biggest bang for your buck.”

What is hoped for the future, after all the genetic and epigenetic clues are sorted out, is an answer that could both treat and prevent various destructive dependencies. This might be accomplished with the help of a tool called the GARS, or Genetic Addiction Risk Score, a genetic test that can identify reward deficiency syndrome among persons in recovery.

These speculations bring up more questions, however, because people who achieve recovery from one addiction have been known to “switch addictions”. It has been observed for decades that AA members veer toward excessive fondness for any sweet refreshments served at the meetings, and are apt to develop an affinity for coffee that they never experienced before.

Anecdotally, a person who enters a residential detox facility to unhook from alcohol or opium might even be warned by established residents to, for instance, take up smoking cigarettes. As one serial relapser phrased it, “the addiction needs someplace to go.” This tendency to transfer is also called cross addiction, or addiction interaction disorder.

Is it possible that the restoration of a person’s dopamine homeostasis, through administration of tailored neuronutrients, could free them from all addictions in one masterful and definitive stroke?

Written by Pat Hartman. First published March 14, 2025.

Source:

“When the Thrill is Gone: Reward Deficiency Syndrome,” Psychology Today, August 19, 2013.

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