Take our Addiction Test

Find a therapist to overcome addiction

Scientific breakthroughs often begin with unexpected observations made while caring for patients.

The same reward biology helps explain addiction, binge eating, obesity, and GLP-1 treatment of SUDs.

GLP-1 therapies reveal how gut hormones influence reward, craving, and addictive behaviors.

More than 50 years ago, I began my career believing I’d spend my life studying addiction. I never imagined the journey would lead to obesity medicine and compulsive eating—from Gatorade to Ozempic.

Looking back, what surprises me most is not where the science ended up, but how often progress began with unexpected observations made caring for patients. One of my earliest mentors at the University of Florida was the late Robert Cade, M.D., the brilliant nephrologist who invented Gatorade to prevent dehydration in athletes.

Dr. Cade taught me that a scientifically perfect oral rehydration solution accomplishes nothing if people refuse to drink it. After listening to his wife's advice, he added lemon flavoring and later carbohydrates to his electrolyte mixture, making Gatorade useful and palatable. This always reminded me that physiology and behavior are inseparable.

I certainly never imagined that, decades later, gut physiology would become central to my own work through GLP-1 biology. But Cade's lesson stayed with me.

In 1969, Woodstock proved an unexpected natural experiment in competing rewards. Food, music, sex, social connections, and psychoactive drugs all competed for attention. I found myself wondering whether the brain prioritized drugs over natural rewards. I had no way to test that idea, but the question never left me.

During my Yale fellowship in the 1970s, I became immersed in the neurobiology of addiction, studying opioid actions, withdrawal, craving, and compulsive drug use. One of my mentors, Eugene Redmond, M.D., conducted research on the island of St. Kitts. He described watching free-ranging vervet monkeys actively seeking fermented sugar cane and even soft drinks provided by local residents. Because fermented sugar cane naturally contains alcohol, their attraction to both suggested that sugar and alcohol might engage related brain reward processes.

Meanwhile, my patients at Yale taught me equally important lessons. At Herb Kleber's New Haven storefront addiction clinics, cigarette smokers gained weight after quitting. Conversely, cocaine users often forget to eat. Patients withdrawing from opioids developed intense cravings for sweets. During a New Haven blizzard interrupting daily methadone treatment, some patients described eating large amounts of sugar, drinking vodka, or even recreating the ritual of heroin use by heating sugar cubes in spoons to ease withdrawal. Again and again, food and drugs appeared to substitute for one another in remarkably predictable ways.

The opioid, cocaine, and speedball epidemics created another unexpected observation. Residential programs originally designed for........

© Psychology Today