Interview on How Addiction Affects the Brain

Dr. Kathryn Cunningham; Image used with her permission.
Dr. Kathryn Cunningham

In this interview on how addiction affects the brain, Dr. Kathryn A. Cunningham shares some of the information revealed during her extensive research on this topic. Learn about the factors that increase the chance of developing an addiction, as well as whether the effects of addiction can be reversed with long term recovery.

Interview on How Addiction Affects the Brain


Kathryn A. Cunningham, Ph.D. directs a research program for addictive and compulsive disorders (e.g., binge eating, obesity), and she is also considered one of the world leaders in the study of the neurotransmitter serotonin and its involvement in these devastating medical conditions. In particular, Dr. Cunningham and her team have advanced the understanding of addiction neuroscience to suggest the potential for novel medications that can reduce craving during rehabilitation and extend abstinence. She is also active in her community and currently serves on the Board of Directors for the Alcohol and Drug Abuse Women's Program in Galveston, Texas. She lectures on drug abuse, addiction and mental health at Galveston College and community treatment programs.

Addiction and Brain Chemistry

LoveToKnow (LTK): Dr. Cunningham, how do drugs and alcohol affect brain chemistry in users?

Dr. Cunnigham (DC): Single use of a drug or alcohol has what we call an "acute" effect on brain chemistry that depends on which drug is used. Abused drugs share a commonality in producing a burst of dopamine, the "feel good" chemical, upon acute use. This dopamine release triggers a cascade of other neurochemical changes that culminate in the entire subjective experience of a drug - the good, bad and ugly.

Repeated use of a drug or alcohol induces an array of changes in how the brain and body function. The initial high is due to the release of pleasure chemicals (dopamine). With regular use and escalating to abuse, the core brain pathways that normally control reward, motivation and behavioral inhibition are highjacked, and these normal functions become progressively disrupted. The transition from use to abuse to addiction is rooted in the genes and proteins of the brain that respond to the drug of choice or alcohol. Thus, the addicted brain becomes biologically distinct from the normal brain and requires medically therapeutic solutions to rebalance brain function (and behavior). In short, addiction is a brain disease. Even though the initial decision to use an abused substance may be voluntary, it is now clear that the transition from drug use to addiction is genetically and biologically influenced.

Factors that Increase Risk for Developing Addiction

LTK: Are some people more vulnerable to addiction because of their brain chemistry?

DC:There are distinct differences in vulnerability to addiction. Many people try drugs, but only a few become addicted. We have some knowledge about what drives vulnerability (or resistance) to addiction. Genetics are a factor. For instance, there is clear evidence that addictions are among the most heritable psychiatric disorders with heritability the greatest for cocaine. This may seem paradoxical, but it makes sense that susceptibility is genetically influenced. However, the ultimate magnitude of impact is dependent upon lifestyle choices (as for heart disease, obesity, etc). There is also evidence that cocaine and opiates are the most addictive substances, and these are also the most heritable addictions, suggesting inheritance of variation in core neurobiological basis of addiction.

A second key factor is that addiction is a developmental disorder beginning in adolescence. There is a very low chance of developing addiction if drug use begins in later adulthood. We have good evidence now that adolescents are not little adults. Rather, their brain architecture changes dramatically through adolescence with the ability to integrate information from their environment, to reason and control "executive" function maturing very late in development. This may help explain why teens are more likely to take risks, are vulnerable to drug use as a high risk behavior, and how drugs at this critical time may affect development of addiction. Thus, doing drugs while the brain is in a major developmental period may profoundly impact later outcomes.

LTK: Do addictive substances affect men and women in the same way?

DC: No. While men are more likely to abuse drugs, women are more likely to become addicted. Some of this is driven by social factors since men and women differ in their access to drugs and other factors that control drug use. However, it is clear that sex hormones influence brain chemistry and provide differential set points in men and women for how the brain responds to drugs.

LTK: Can the brain recover from the previous damage caused by abusing these substances if a person abstains from future drug and alcohol use?

DC: Many of the effects of repeated drug use are reversible, although it may take some time. However, some drugs (like methamphetamine) cause damage to neurons, and some of this damage could be permanent.

LTK: Can these changes in brain chemistry affect a person's life span?

DC: This is a very important question. We know, for instance, that dopamine function declines with normal aging. If drug use during adolescence alters the course of maturity of dopamine function, it is possible that aging-related declines on this background could differentially alter brain function. These kinds of questions are under investigation now.

LoveToKnow would like to thank Dr. Kathryn Cunningham for sharing this important information about how addiction affects the brain and wish her success with her continued research.

Interview on How Addiction Affects the Brain