Ronald C. Kessler

Ronald C. Kessler (born April 26, 1947) is an American professor at Harvard Medical School. His research focuses on the precision treatment of mental illness to determine the appropriate intervention for specific patients. He ranks among the most highly cited researchers in the world, with an h-index of 349 as of June 2025. He developed the Kessler psychological distress scale, which is designed to measure non-specific psychological distress.

Kessler was born in Bristol, Pennsylvania on April 26, 1947. He graduated with a B.A. in sociology from Temple University in 1970. He went on to complete his M.A. in sociology in 1973 and Ph.D. in sociology in 1975 from New York University.

Kessler was a predoctoral Fellow at Health Service Research at Montefiore Hospital in Bronx, New York, from 1972 to 1974. He was a research associate at New York State Psychiatric Institute from 1975 to 1976 and at the Centre for Policy Research from 1976 to 1977.

He was a postdoctoral Fellow at the Department of Psychiatry, University of Wisconsin–Madison from 1977 to 1979. He then worked on the faculty at the University of Michigan for 17 years. He became a professor of health care policy at Harvard Medical School in 1996.

In 2008, Kessler was elected a member of American National Academy of Sciences in the categories of Social Sciences and Political Science.

Kessler is the principal investigator of the National Comorbidity Survey (NCS). The NCS was the first nationally representative survey of the prevalence and correlates of psychiatric disorders in the United States. The survey was carried out in 1991 and 1992.

He co-developed his psychological stress scale in 1992 alongside Dan Mroczek.

He is also the principal investigator of several NCS extensions, including a 10-year follow-up of the baseline NCS sample and a replication of the NCS in 2001 and 2002 to study changes in mental health and treatment of mental disorders in the U.S. over the decade of the 1990s.