Inflamed in the Brain

What is the connection between inflammation and mood disorders?


Roger S. McIntyre, MD, FRCPC, of the University of Toronto and the University Health Network presented on inflammation in individuals with mood disorders at the 2021 Neuroscience Education Institute (NEI) Congress Friday, November 5, in Colorado Springs, Colorado.

In his presentation, titled “Inflamed in the Brain: The Role of Inflammation in Psychiatry,” McIntyre discussed the physiology of the inflammatory system and how inflammation correlates in individuals with mood disorders, as well as some common anti-inflammatory interventions for these individuals. He stated that there is a high prevalence of inflammation in individuals with mood disorders such as depression and bipolar disorder: About 25% to 30% of individuals with major depressive disorder (MDD) or bipolar disorder have a CRP of higher than 3 mg per liter, and 50% have a CRP of higher than 1. Using COVID-19 as an example, he reported that individuals with MDD or bipolar disorder were more likely to contract, be hospitalized, and die due to COVID-19. Further, one-third of outpatients and one-half of inpatients with COVID-19 have since developed a neurologic or psychiatric disorder.1

McIntyre shared that some sources of pro-inflammatory balance in mood disorders include genetics, as well as environmental factors like social determinants (eg, poverty), behavior (eg, smoking cigarettes), diet, sleep disturbance/chronobiology, comorbidity (eg, obesity), microbiota, trauma, and loneliness. He also recommended several anti-inflammatory treatment methods, including mindfulness, exercise, restorative sleep, Mediterranean-like diet, and greater social network ties.1

According to McIntyre, having an increased understanding of the link between inflammation and psychiatric disorders has become particularly important, given the association between COVID-19 and mood disorders.“We have a serious public health crisis right now,” he said during his presentation. “We all want to see our patients get vaccinated to protect their health … but I think we have to advocate for our patients. And we have to be very vigilant because I don’t think we know if a year from now—or 2 years from now or 3 years from now—whether the immunocompetence can be assumed to be identical. I don’t know the answer to that. It’s a really interesting hypothesis that if we can better treat them with psychotherapy, CBT, mindfulness, and good antidepressants they can tolerate, this might be the extra boost they need.”

McIntyre is a professor of psychiatry and pharmacology at the University of Toronto and head of the Mood Disorders Psychopharmacology Unit at the University Health Network in Toronto, Canada. In his research, he aims primarily to characterize the neurobiology, phenomenology, and novel therapeutics of mood disorders.


1. McIntyre RS. Inflamed in the brain: the role of inflammation in psychiatry. Presented at 2021 NEI Congress. November 5, 2021.