medicine | iowa

MSTP student Nasir Naqvi finds strong link between addiction and feelings

It’s only natural to have a craving from time to time. But for some, those cravings are irresistible and more serious than occasionally wanting another piece of chocolate. Addiction to smoking is one of the most difficult urges to control, and the negative effects on the health of individuals and their families are staggering.

Nasir Naqvi, a 2007 graduate of the UI Carver College of Medicine Medical Scientist Training Program, and a team of researchers, identified a part of the brain that plays an important role in addiction. They found that patients who experienced damage to a silver dollar-sized brain region called the insula were significantly more likely to lose their addiction to smoking than patients with lesions on other parts of the brain. The study was published in the Jan. 26, 2007 issue of Science. Naqvi was first author on the paper.

“We’ve known for some time that the insula is part of a network of brain regions that “lights up” when people have cravings for all sorts of drugs, including cigarettes. Despite this, there hasn’t been much focus on the insula, because animal models haven’t shown that it plays a role in addiction,” said Naqvi. “The insula may play a role in mental states that are unique to humans, such as feeling the urge to smoke when trying to abstain from smoking. I was interested in the insula because I was curious about addiction as a human experience, not simply a set of behaviors that you can teach a rat. Based on our study, it now appears that the human side of addiction must be considered.”

The study included 19 patients with insula damage, and 50 patients with damage to other regions of the brain. All of the patients smoked more than five cigarettes per day for more than two years prior to their injury. The patients with insula damage were much more likely to have quit smoking easily, immediately, and without relapse than patients with damage to other brain areas. In fact, in most cases, damage to the insula caused patients to completely lose their urge to smoke. In the study, 12 of 19 patients with insula damage lost their addiction compared to four of 50 patients with non-insula damage. The research project took approximately one year to complete.

“I wasn’t surprised that smokers with damage to the insula had some reduction in their urges, since this was our original hypothesis. What was surprising and really fascinating was that the reduction was quite profound and resulted in a change in the addictiveness of smoking at a clinically significant level,” said Naqvi. “It was only after the paper was published and there was so much excitement about the finding that I realized this would change the way people think about addiction. There would now be attention focused toward the role of conscious feelings.”

After completing his undergraduate neuroscience degree at New York University, he worked as a research assistant at Rockefeller University studying the neural systems underlying vocal communication in songbirds. Through this experience he became interested in how the brain represents information that has social and emotional relevance. Though the work was with birds, it inspired him to learn more about the human brain.

For him, pursuing an MD/PhD degree was a natural fit. As a future psychiatrist, his clinical and research interests will center on understanding the mind and brain as a unified entity. “I’ve wanted to be a physician since before I can remember. My interest in neuroscience arose more recently, which led me to become interested in psychiatry. My goals as a neuroscientist and a psychiatrist are similar. I like to understand what makes people tick. I love figuring things out and that’s what medicine and science is about,” said Naqvi. Naqvi will begin his psychiatry residency at Columbia University Medical Center - New York Presbyterian Hospital in June.

Naqvi’s advisor and a member of the research team, Antoine Bechara, PhD, associate professor of psychology and neuroscience at the University of Southern California (USC) and adjunct associate professor of neurology at the UI, is interested in pursuing pharmacological therapies for addiction. Bechara believes the insula plays a role in maintaining addiction of many different kinds, and speculates that there may be implications for treating obesity.

The study also included contributions from David Rudrauf, (’05 PhD), UI postdoctoral research scholar in neurology and Hanna Damasio, MD, the Dana Dornsife Professor of Neuroscience and director of the Dana and David Dornsife Cognitive Imaging Center, and professor of psychology, neuroscience and neurology at USC. Damasio also is a distinguished adjunct professor at the UI.