Surprising: Is Depression the Result of Inflammation in the Body?

One in six people will experience depression during their lifetime, yet despite decades of research, many questions regarding the biological mechanisms behind the disease remain unanswered.

Depression, which profoundly affects the quality of life, has been explained over the years with various theories and treatments developed. However, their effectiveness remains limited. A new study, recently published by Prof. Raz Jeremiah from the Department of Psychology at the Hebrew University, offers new insights and challenges conventional beliefs about the causes of the disease.

According to Prof. Jeremiah, the central theory underlying depression treatment to date has been that the disease results from an imbalance in serotonin and norepinephrine levels — two chemicals that play a key role in regulating mood in the brain. Based on this theory, medications, mainly from the SSRIs family, were developed with the goal of increasing serotonin concentration. These drugs have become a common means of treating depression and are available in most households worldwide.

However, recent research reveals significant limitations in this theory. "One-third of patients do not respond at all to existing medications," notes Prof. Jeremiah. "For those who do respond, it often takes a long time to find the most suitable drug, and sometimes multiple medications need to be switched to achieve a satisfactory result." He adds that during the waiting period for the medication's effect, individuals suffering from depression endure significant physical and mental distress.

Depression and Inflammation: The Surprising Link

The comprehensive review conducted by Prof. Jeremiah suggests an entirely new direction for understanding depression: the link between the disease and inflammatory processes in the body. "We know today that depression affects not only the brain but the entire body," he explains. Studies have shown that some depression sufferers have elevated levels of inflammatory markers in their blood. These markers, such as inflammatory cytokines, can affect brain function and cause mood changes.

Prof. Jeremiah describes a situation where the immune system operates chronically, even when unnecessary, triggering inflammatory responses that impact communication between brain cells. "Chronic inflammation can disrupt the chemical balance in the brain and lead to the emergence of depressive symptoms," he explains.

Conclusion: New Hope for Depression Sufferers

The new theory presents an opportunity to change the approach to treating the disease. Rather than focusing solely on brain chemistry, researchers aim to understand how processes throughout the body influence mood. While the road to a fundamental change in treatment is still long, the new insights offer real hope for improving the lives of those suffering from depression and for more effectively coping with the disease.