The study included 69 individuals with IED, 61 nonaggressive individuals with other psychiatric disorders, and 67 individuals with neither IED nor other psychiatric disorders. The researchers measured the levels of two inflammatory cytokines—interleukin 6 and C-reactive protein—in subjects' blood. Levels of the two cytokines were significantly higher in IED subjects than in the other two groups, even when potentially confounding factors such as a history of stressful life events or depression were considered. "These data suggest a direct relationship between plasma inflammatory processes and aggression in humans," Coccaro and colleagues concluded.
It's also possible that inflammatory cytokines actually contribute to anger and aggression, the researchers noted. In one study they cited, for example, infusion of inflammatory cytokines into the brains of experimental animals made the animals aggressive. In another study, individuals treated with inflammatory cytokines reported feeling increasingly angry and aggressive.
More information about IED and possible treatments for it are reported in the Psychiatric News articles "A Small Protein May Play a Big Role in Controlling Aggression" and "IED Quite Common, but Treatments Elusive."
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