Anti-Inflammatory Treatments May Improve Depressive Symptoms
Studies have found that inflammatory molecules play a role in depression. A recent study by researcher Yu Sun and colleagues used data from clinical trials of anti-inflammatory drugs to show that these drugs also reduced depressive symptoms. The two drugs, which are administered either by a shot or injection into the skin, each consist of antibodies that target the inflammatory molecule IL-6. Sirukumab is being looked at as a possible treatment for rheumatoid arthritis, while siltuximab is a potential treatment for Castleman’s disease, an illness characterized by enlarged lymph nodes. As part of the clinical trials for these drugs, patients with these illnesses responded to survey questions that assessed symptoms of depression and fatigue.
Among patients who reported that they have at least one depressive symptom most of the time and another symptom at least part of the time, the anti-inflammatory drugs significantly improved depressive symptoms compared to placebo. Even when the patients’ inflammatory illnesses did not respond to the anti-inflammatory treatments, their depressive symptoms did improve (symptoms of fatigue did not). An improvement in depressive symptoms was observed after 6 weeks in patients with Castleman’s disease taking siltuximab, and after 12 weeks in patients with rheumatoid arthritis taking sirukumab.
In the sirukumab study, the level of the inflammatory molecule IL-6 in participants’ blood before the study was linked to the magnitude of improvement in their depressive symptoms during the study. IL-6 is elevated in many patients with unipolar and bipolar depression. It is possible that antibodies that target IL-6 could be used to treat primary depression (in the absence of other inflammatory disorders).