Cytokines are proteins released by immune system cells that regulate immune responses. Proinflammatory cytokines coordinate inflammation processes in the body. Increased levels of proinflammatory cytokines or PICs have been linked with depressive symptoms, including:
- · dysphoria (opposite of euphoria)
- · anhedonia (inability to experience pleasure)
- · fatigue
- · apathy
- · A sense of helplessness
People with depression have increased levels of preinflammatory cytokines—this may help to explain the reason inflammatory diseases and autoimmune diseases are often associated with depression, as well.