Published: 11-10-2023 11:40 | Updated: 22-03-2024 11:40

Changing the view on placebo and long-term pain

Karin Jensen uses brain imaging to understand why chronic pain occurs and what happens in the body when placebo, the patient's positive expectations, affect the outcome of a treatment.

Professor Karin Jensen. Photo: Erik Flyg

What are you researching?

“I do research on pain and placebo. I want to understand what happens in the brain when people experience pain, and examine how perception of pain can be affected by cognitive factors such as expectations. The brain imaging technique fMRI is my most important tool.”

What have you discovered?

“I have contributed to the emergence of an overall picture of how placebo works. We now know that placebo can create visible physical changes in the body and often represents a significant portion of a treatment response.

My most important contribution is that I have demonstrated that placebo is not an exclusively intellectual process, as was previously believed. Placebo also has an effect through the brain's lower structures, outside our consciousness. It therefore works in young children, people with intellectual disabilities and older people with dementia.

Within pain research, I have been part of a movement that has worked experimentally to elucidate what happens when a person develops chronic pain. We have noticed that the central nervous system changes in several ways. This has contributed to the acceptance of so-called nociplastic pain as a medical term.

In the future, I would like to find out who is at a high risk of developing long-term pain. For this purpose, we are building a large database with genetics, brain imaging and other data, where we will be following research subjects for a long period of time.”

What do you hope that your research will lead to?

“I think that it may lead to new pain treatments in the long run, and tools for pain diagnostics and prevention before that. I also hope that the healthcare system will harness knowledge about the placebo effect to shape patients' expectations and obtain better treatment results.”

Text: Anders Nilsson, in translation from Swedish
First published in the booklet ‘From Cell to Society 2023’

About Karin Jensen

Professor of Cognitive Neuroscience at the Department of Clinical Neuroscience

Karin Jensen was born in Mantorp, Östergötland in 1979. She earned her degree in psychology at Uppsala University in 2005 and defended her doctoral thesis at Karolinska Institutet in 2009. She completed her postdoc at Harvard Medical School in 2010-2013 and continued as Assistant Professor between 2013 and 2017. In 2014-2017, she gradually moved her research to Karolinska Institutet and established her own group.

She became a docent in 2019 and has had the role of Deputy Head of Department since that same year.

Karin Jensen was appointed Professor of Cognitive Neuroscience at Karolinska Institutet on 1 July 2023.

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