There's a well-established link between depression and chronic low-grade inflammation. Now, a new meta-study shows that treating the inflammation can reduce depression in two ways, offering a potential alternative to antidepressants and their side effects.
Since the 1980s, the link between depression and inflammation has been known, although it has more or less remained a kind of chicken-and-egg situation. Do people suffering from chronic inflammation become depressed because of effects like pain, fatigue, and repeated colds, or do they have depression which then leads the body to become inflamed? And in either case, could treating inflammation also treat depression?
Previous studies have been mixed on the issue, although it is now generally accepted that if a person's depressive symptoms are brought on exclusively by inflammation, then yes, treating it can help.
Backing up this idea is new research out of Brigham and Women's Hospital. Researchers there felt that many previous studies looking at how anti-inflammatory treatments fought depression were flawed because they examined the use of such treatments over a wide range of depressed individuals – not necessarily people who were both depressed and suffering from chronic inflammation.
So they conducted a meta-analysis in which they found 11 different studies where it was confirmed that the study participants had both chronic inflammation and depression and were then treated with anti-inflammatories. That honed their meta-study down to a relatively small group of 321 participants. Still, they found promising results.
"We found that anti-inflammatory medications significantly reduced both depressive symptom severity and anhedonia at the study endpoint," says study lead Naoise Mac Giollabhui. Anhedonia is a common symptom of depression in which people have a decreased ability to feel pleasure.
In their analysis, the researchers found a Hedges’ g of 0.4 for anhedonia. That’s basically a standardized measure of how much better the treatment group did compared to the placebo group. In practical terms, if you randomly picked someone from each group, the person on the anti-inflammatory treatment would report improved symptoms roughly 60% of the time.
For overall depressive symptoms, the Hedges’ g value came in at 0.35.
While Giollabhui says that his team's study does, in fact, confirm that anti-inflammatories given to depressed individuals who have "dysregulated immune systems" can improve their symptoms, he feels more research is needed.
"There’s a lot of work that needs to be done to develop immune biomarkers that more accurately identify who will benefit from anti-inflammatory treatment for depression and to develop treatment approaches that selectively target dysfunctional inflammatory physiology," he concludes. "At the moment, some of the more potent anti-inflammatory medications have serious side-effects that make them sub-optimal for use in a clinical setting."
The study has been published in the American Journal of Psychiatry.
Source: Mass General Brigham
