Evidence suggests poor sleep increases risk of depression

“When you are tired, when you’re worn out, then everything becomes more of a challenge for you,” says Dr. Adam Moscovitch, medical director of the Canadian Sleep Institute in Toronto and Calgary. “Your confidence is affected, your ability to trust yourself. So there is a higher likelihood you’ll be ruminating about, are you doing things right? It significantly affects, from the psychological standpoint, the (risk) of mental illness developing.”

Poor sleep can weaken the immune system and affect concentration, functioning and judgment. It causes changes in appetite and sexual interest. Studies have found that people who sleep six hours or less a night have an increased risk of high blood pressure, heart attacks and stroke.

But now, a growing body of evidence suggests poor sleep may actually precede some mental illnesses, in particular depression, mood and anxiety disorders. University of California, Berkeley and Harvard Medical School researchers have shown that lack of sleep amplifies our emotional “brain state.” The amygdala, the emotional part of the brain linked to depression and other psychiatric conditions, appears to become more active when deprived of sleep.