A growing body of research on conditions from bipolar disorder to schizophrenia to depression is starting to suggest a tighter link than was previously realized between ailments of the mind and body. Activation of the immune system seems to play a crucial role in both.
"We just didn't understand how much of a role the immune system plays in how we think and feel and act," says Andrew Miller, a professor of psychiatry at Emory University. "An overactive immune system or when there's something going on in the immune system, it can have consequences on the brain."
An immune response, including inflammation, new research suggests, may help explain why:
• Brain conditions such as multiple sclerosis, Parkinson's and Alzheimer's disease all affect mood;
• About one in four people hospitalized with schizophrenia had a urinary tract infection when admitted to the hospital;
• Mothers with auto-immune conditions such as lupus are more likely to have a child on the autism spectrum;
• People with higher rates of inflammation are more likely to show signs of depression than those with healthy immune function. A study in mice presented earlier this month at the Society for Neuroscience's annual convention showed that the immune changes came before the emotional ones.