Just as we once knew that infectious diseases killed, but didn’t know that germs spread them, we’ve known intuitively that loneliness hastens death, but haven’t been able to explain how. Psychobiologists can now show that loneliness sends misleading hormonal signals, rejiggers the molecules on genes that govern behavior, and wrenches a slew of other systems out of whack. They have proved that long-lasting loneliness not only makes you sick; it can kill you. Emotional isolation is ranked as high a risk factor for mortality as smoking. A partial list of the physical diseases thought to be caused or exacerbated by loneliness would include Alzheimer’s, obesity, diabetes, high blood pressure, heart disease, neurodegenerative diseases, and even cancer — tumors can metastasize faster in lonely people.
I plan to take this with a grain of salt. In fact, several grains, which probably won’t affect my blood pressure in the least.