A comprehensive study from the Netherlands reveals a consistent connection between chronic low-grade inflammation and symptoms of depression, anxiety, and subtle cognitive impairments, particularly in memory and attention.
Using both observational data and genetic analyses from over 55,000 participants in the Lifelines cohort, researchers found that higher levels of inflammatory markers like C-reactive protein (CRP) and GlycA correlate with increased risk of mental health symptoms and reduced cognitive performance.
Depression, a leading cause of disability worldwide, often involves cognitive difficulties that worsen long-term outcomes. While inflammation is the body’s natural defense against injury or infection, persistent inflammation may disrupt brain function.
Previous research has shown elevated inflammatory proteins in people with depression, but whether these proteins cause mental illness or result from other health issues has remained unclear.
The study’s lead author, Naoise Mac Giollabhui of Massachusetts General Hospital and Harvard Medical School, explained the challenge of disentangling immune dysfunction from related factors like stress, diet, and substance use.
By combining genetic risk scores with biomarker data, the team provided stronger evidence that inflammation may causally influence certain mental health outcomes.
Specifically, genetic predisposition to higher CRP levels was linked to greater anxiety risk, while GlycA-related genetics were associated with major depressive disorder. Elevated CRP also correlated with negative emotional states and minor declines in executive function, attention, and psychomotor speed.
Co-author Chloe Slaney of the University of Bristol noted that although the observed effects were small, the consistency across different analyses supports the role of immune activity in emotional and cognitive health.
The findings, published in Translational Psychiatry, add to growing evidence that targeting inflammation could lead to improved treatments for depression and anxiety.
Mac Giollabhui is currently conducting clinical trials to test whether reducing immune signaling can alleviate mood and cognitive symptoms in patients with high inflammation, aiming to develop more effective therapies.
This study underscores the complex interplay between the immune system and mental health, suggesting inflammation as a promising avenue for future research and treatment innovation.
