RICHARD ROSS, MD: Certain neurochemicals are released in our brain, so that stress can in fact lead to heightened vigilance, heightened arousal and everything that counters the tendency to sleep.
ANNOUNCER: While the stress often results from the appearance of the usual suspects -- problems with work, loved ones, worries about health -- some forms of anxiety can appear with no apparent cause. And the feeling is constant.
RICHARD ROSS, MD: Anxiety disorders are perhaps the most prevalent mental disorder in the United States, including phobias and generalized anxiety disorder, obsessive-compulsive disorder, panic disorder.
DAVID P. WHITE, MD: General anxiety disorder is a condition with people that just have heightened anxiety at all times, and these people are, almost universally, going to have a certain amount of difficult sleeping.
RICHARD ROSS, MD: Panic disorder is characterized most specifically by unanticipated, spontaneous attacks of quite severe anxiety. A person feels heart rate going up, sweating.
ANNOUNCER: If the panic attack happens well before bedtime, sleep may not suffer. But troubled sleep does ensue when attacks happen near bedtime or even during sleep.
RICHARD ROSS, MD: A person typically awakens from what's called a nocturnal panic attack feeling quite anxious, may have some recall of the event the next morning, and it can actually be quite disturbing to the person.
ANNOUNCER: But you don't have to have an anxiety disorder to suffer from the kind of anxiety that makes for a fretful night.