Many of us toss and turn or watch the clock when we can’t sleep for a night or two. But for some, a restless night is routine.
More than 40 million Americans suffer from chronic, long-term sleep disorders, and an additional 20 million report sleeping problems occasionally, according to the National Institutes of Health.
Stress and anxiety may cause sleeping problems or make existing problems worse. And having an anxiety disorder  exacerbates the problem.
Sleep disorders are characterized by abnormal sleep patterns that interfere with physical, mental, and emotional functioning. Stress or anxiety can cause a serious night without sleep, as do a variety of other problems.
Insomnia is the clinical term for people who have trouble falling asleep, difficulty staying asleep, waking too early in the morning, or waking up feeling unrefreshed.
Other common sleep disorders include sleep apnea (loud snoring caused by an obstructed airway), sleepwalking, and narcolepsy (falling asleep spontaneously). Restless leg syndrome and bruxism (grinding of the teeth while sleeping) are conditions that also may contribute to sleep disorders.
Either one. Anxiety causes sleeping problems, and new research suggests sleep deprivation can cause an anxiety disorder.
Research also shows that some form of sleep disruption is present in nearly all psychiatric disorders. Studies also show that people with chronic insomnia are at high risk of developing an anxiety disorder.
The risks of inadequate sleep extend way beyond tiredness. Sleeplessness can lead to poor performance at work or school, increased risk of injury, and health problems.
In addition to anxiety and mood disorders, those with sleep disorders are risk for heart disease, heart failure, irregular heartbeat, heart attack, high blood pressure, stroke, diabetes, and obesity.
If you suspect you have a sleep disorder, visit a primary care physician, mental health professional, or sleep disorders clinic. Treatment options include sleep medicine and cognitive-behavior therapy , which teaches how to identify and modify behaviors that perpetuate sleeping problems.
Treatment options for an anxiety disorder also include cognitive-behavior therapy, as well as relaxation techniques, and medication . Your doctor or therapist may recommend one or a combination of these treatments. Learn more about treatment options .
To reduce anxiety and stress:
To sleep more soundly:
American Sleep Association 
Sleep Apnea 
Sleep Disorders Health Center  (WebMD)
Can’t Sleep? Sleep Expert Has the Answers 
ADAA Member Philip Muskin Discusses Sleep  (CBS News)
Sleepdex website