Irving Kirsch

Irving Kirsch (born March 7, 1943) is an American psychologist and academic. He is the Associate Director of the Program in Placebo Studies and a lecturer in medicine at the Harvard Medical School and Beth Israel Deaconess Medical Center. He is also professor emeritus of psychology at the Universities of Hull and Plymouth in the United Kingdom, and the University of Connecticut in the United States. Kirsch is a leading researcher within the field of placebo studies who is noted for his work on placebo effects, antidepressants, expectancy, and hypnosis. He is the originator of response expectancy theory, and his analyses of clinical trials of antidepressants have influenced official treatment guidelines in the United Kingdom. He is the author of the 2009 book The Emperor's New Drugs, which argued most antidepressant medication is effective primarily due to placebo effects.

Biography
The son of Jewish immigrants from Poland and Russia, Kirsch was born in New York City on March 7, 1943. Kirsch received his PhD in psychology from the University of Southern California in 1975. While a graduate student, he produced, in conjunction with the National Lampoon, a hit single and subsequent record album entitled The Missing White House Tapes, which were crafted by doctoring tape recordings of Richard Nixon’s speeches and press conferences during the Watergate hearings. The album was nominated for a Grammy award as Best Comedy Recording in 1974.

In 1975, Kirsch joined the psychology department at the University of Connecticut, where he worked until 2004, when he became a professor of psychology at the University of Plymouth. He moved to the University of Hull in 2007 and joined the faculty of the Harvard Medical School in 2011. Kirsch has authored or edited 10 books and more than 200 scientific journal articles and book chapters.

Response expectancy theory
Kirsch’s response expectancy theory is based on the idea that what people experience depends partly on what they expect to experience. According to Kirsch, this is the process that lies behind the placebo effect and hypnosis. The theory is supported by research showing that both subjective and physiological responses can be altered by changing people’s expectancies. The theory has been applied to understanding pain, depression, anxiety disorders, asthma, addictions, and psychogenic illnesses.

Research on antidepressants
Kirsch’s analysis of the effectiveness of antidepressants was an outgrowth of his interest in the placebo effect. His first meta-analysis was aimed at assessing the size of the placebo effect in the treatment of depression. The results not only showed a sizeable placebo effect, but also indicated that the drug effect was surprisingly small. This led Kirsch to shift his interest to evaluating the antidepressant drug effect.

The controversy surrounding this analysis led Kirsch to obtain files from the U.S. Food and Drug Administration (FDA) containing data from trials that had not been published, as well as those data from published trials. Analyses of the FDA data showed the average size effect of antidepressant drugs to be equal to 0.32, clinically insignificant according to the National Institute for Health and Clinical Excellence (NICE) 2004 guidelines, requiring Cohen's d to be no less than 0.50. No evidence was cited to support this cut-off and it was criticised for being arbitrary; NICE removed the specification of criteria for clinical relevance in its 2009 guidelines.

Kirsch challenges the chemical-imbalance theory of depression, writing "It now seems beyond question that the traditional account of depression as a chemical imbalance in the brain is simply wrong." In 2014, in the British Psychological Society's Research Digest, Christian Jarrett included Kirsch's 2008 antidepressant placebo effect study in a list of the 10 most controversial psychology studies ever published.

In September 2019 Irving Kirsch published a review in BMJ Evidence-Based Medicine, which concluded that antidepressants are of little benefit in most people with depression and thus they should not be used until evidence shows their benefit is greater than their risks.

Research on hypnosis
Kirsch has focused some of his research on the topic of hypnosis. The basis of his hypnosis theory is that placebo effects and hypnosis share a common mechanism: response expectancy. Kirsch's idea on this topic is that the effects of both hypnosis and placebos are based upon the beliefs of the participant. He has characterized clinical hypnosis as a "nondeceptive placebo."