Some depression might have roots in immune-generated inflammation

Research has shown that depressed or stressed-out people tend to be more susceptible to medical ailments, such as infectious diseases and perhaps even cancer. But the correlation might also work in the opposite direction, Miller explained. People who are critically ill have about five to 10 times higher rates of depression, and that might not just be due to battling their illness, he noted. It could be stemming from underlying inflammation—a common bodily response to illness or injury.