Depression: Psychiatrist helps people to understand, cope with very common problem
The issue arises when depression is persistent and you have clinical depression. Clinical depression is a distinct brain state, according to Jennings.
"Most people think that if you take an individual and you stress that individual long enough, something is going to break," he said.
"Some people get ulcers, some people get depressed," Jennings said. "Depression does have a genetic component. About 50 percent of serious depressive illness runs in the family. Now I'm not talking about manic depressive illness. I'm just talking about clinical depression."
Certain symptoms are important. First of all, the people have to be persistently depressed, he said.
"Somebody who is depressed on a Tuesday and is fine the rest of the week, that's different," Jennings said. "To have clinical depression, you have to be consistently depressed for at least a couple of weeks, if not longer."
He said severe depression is a brain disease. Patients can be placed in scanners to measure their brain metabolism and those with severe depression will show as abnormal. "It's a physiologic state," Jennings said.