An Inflammatory State Impedes Treatment for Bipolar Disorder
A 2017 study by in the Journal of Clinical Psychiatry links inflammation to a poor antidepressant response in bipolar disorder. Many previous studies have found that elevated inflammatory markers are common in mood disorders, and that an inflammatory state seems to prevent response to certain therapies.
Researcher Francesco Benedetti and colleagues report that high levels of inflammatory cytokines (a type of small proteins) predicted a worse response to treatment with sleep deprivation and light therapy for bipolar depression. This treatment typically brings about a rapid antidepressant response.
Benedetti and colleagues measured 15 immune-regulating compounds in 37 patients who were experiencing an episode of bipolar depression and 24 healthy volunteers. Among those participants with bipolar disorder, 84% had a history of non-response to medication. Twenty-three of the 37 patients, or 62%, responded to the sleep deprivation/light therapy combination. Those who did not had higher levels of five cytokines: interleukin-8, monocyte chemoattractant protein-1, interferon-gamma, interleukin-6, and tumor necrosis factor-alpha.
Body mass index was correlated with cytokine levels and also reduced response to the treatment.
The finding supports a link between the immune system and mood disorders. Evaluating a patient’s level of inflammation may, in the future, allow doctors to predict the patient’s response to a given therapy. Patients with high levels of inflammation might benefit most from treatments that target their immune system.
