Charles P. O'Brien

In the US, O'Brien has chaired or served as a member of many Institute of Medicine committees dealing with science and drug abuse policy matters. From 2007 to 2013, he served as chairperson of the Substance Use Disorders Committee of the American Psychiatric Association. The purpose of this committee was to revise the primary classification system, known as DSM-5, that psychiatrists use in diagnosing mental illnesses, including addiction disorders.

Naltrexone, an opioid receptor antagonist, was already in use by the early 1980s as a medication for treating addiction to heroin and other opioids, but not alcohol addiction. Based on animal studies, O'Brien in the 1980s theorized that alcohol produced pleasure by releasing endorphins – the brain's naturally occurring opioids. Accordingly, blocking endorphin receptors might help alcoholics resist drinking. In 1983, the Food and Drug Administration (FDA) granted permission to test this theory on patients. With funding provided by the U.S. Veterans Administration Substance Abuse Center in Philadelphia, O'Brien and one of his students, fellow University of Pennsylvania psychiatrist Joseph Volpicelli, and others conducted a study in which all addiction patients received counseling, but half of them also received naltrexone, while the other half received a placebo. During three months of treatment, those receiving naltrexone had fewer relapses to heavy drinking and reported less craving and less pleasure when they did drink. Working from these observations, O'Brien and his colleagues discovered a new treatment for alcoholism using naltrexone. In 1995, the FDA approved naltrexone for the treatment of alcohol dependence, ushering in a new era of alcoholism treatment which, prior to this time, had been limited mainly to psychotherapy and psychosocial interventions such as Alcoholics Anonymous.

While serving as chief of psychiatry at the Veterans Administration (VA) Medical Center in Philadelphia, In 1971 O'Brien founded and became director of a clinical research program consisting of a group of VA and University of Pennsylvania scientists. From 1971 until 2013, he served as director of this research center, called the Center for Studies of Addiction at the University of Pennsylvania. He and the center's other researchers made many discoveries about the treatment of addictive disorders, and published their research findings in more than 500 research papers, all authored or co-authored by O'Brien, and published in peer-reviewed scientific journals. O'Brien and his colleagues at the Center for Studies of Addiction received personal praise, for their innovative research and results in helping patients recover from drug addiction, from U.S. President George H.W. Bush during a September 1991 tour of the center.

There was no validated measure of addiction in the 1970s, so O'Brien began work, together with A. Thomas McLellan, PhD, to develop the "Addiction Severity Index", a tool that was later translated into over 30 languages and which by 2012 was being used throughout the world to determine the extent of patients' problems and tailor appropriate treatment approaches.

O'Brien earned MD and PhD degrees from Tulane University in 1964 and 1966, respectively, and received residency training in internal medicine, neurology and psychiatry at Harvard University, Tulane, the University of London, and the University of Pennsylvania.

Charles P. O'Brien (born August 20, 1939, New Orleans, Louisiana) is a research scientist, medical educator and a leading expert in the science and treatment of addiction. He is board certified in neurology, psychiatry and addiction psychiatry. He is currently the Kenneth E. Appel Professor of Psychiatry, and vice chair of psychiatry, in the Perelman School of Medicine at the University of Pennsylvania.