Causes
Factors that can cause sleep problems are:

• Physical (ulcers)
• Medical (asthma)
• Psychiatric (depression and anxiety disorders)
• Environmental (alcohol use)

Short-term or acute insomnia can be caused by life stresses, such as job loss or change, death of a loved one, moving, an illness or environmental factors (such as light, noise or extreme temperatures).

Long-term or chronic insomnia can be caused by factors such as depression, chronic stress, and pain or discomfort at night.

Other factors that can interfere with sleep include:

• Genetics - Researchers have found a genetic basis for narcolepsy, a neurological disorder of sleep regulation that affects the control of sleep and wakefulness.
• Night shift work - People who work at night often experience sleep disorders because they cannot sleep when they start to feel drowsy. Their activities run contrary to their biological clocks.
• Medications - Many medications can interfere with sleep, such as certain antidepressants, blood pressure medication and over-the-counter cold medicine.
• Aging - About half of all adults over the age of 65 have some sort of sleep disorder, it is not clear if it is a normal part of aging or a result of medications that older people commonly use.

Prevention
In some cases, sleep problems are related to preventable health conditions. Addressing such conditions may help prevent sleep disorders. Example: Experts think that weight loss may help overweight people who have obstructive sleep apnea.

Other times, lifestyle modifications may be needed to prevent a sleep  disorder from developing.
Example: Exercise along with a healthy diet can ward off sleep problems.

Other sleep problems can be avoided with the use of good sleep habits, called sleep hygiene. Below are some suggestions for better sleep:

• Try to go to sleep at the same time each night and get up at the same time each morning. Try not to take naps during the day because naps may make you less sleepy at night.
• Avoid caffeine, nicotine and alcohol late in the day. Caffeine and nicotine are stimulants and can keep you from falling asleep. Alcohol can cause waking in the night and interferes with sleep quality.
• Get regular exercise. Try not to exercise close to bedtime because it may stimulate you and make it hard to fall asleep. Experts suggest not exercising for at least three to four hours before the time you go to sleep.
• Don't eat a heavy meal late in the day.
• Make your sleeping place comfortable. Make the room dark, quiet and not too warm or too cold. If light is a problem, try a sleeping mask. If noise is the problem, try earplugs, a fan or a white noise machine to cover up the sounds.
• Follow a routine to help you relax and wind down before sleep, such as reading a book, listening to music or taking a bath.
• Avoid using your bed for anything other than sleep or sex.
• If you can't fall asleep and don't feel drowsy, get up and read or do something that is not overly stimulating until you feel sleepy.
• If you have trouble lying awake worrying about things, try making a to do list before you go to bed. This may help you to avoid focusing on those worries overnight.