You've likely had nights when you couldn't fall asleep, no matter how desperately you tried.

When you can't sleep, the ticking of the clock only reminds you of your exhaustion and the endless hours until morning. And perhaps you finally drop off around dawn, only to be jarred awake by the alarm an hour later.

Insomnia means having trouble sleeping at night, staying asleep, or both. It's one of the most common sleep disorders. Episodes of insomnia that last a few days at a time are called short-term (acute) insomnia. Ongoing (chronic) insomnia is often diagnosed when you have ongoing problems with sleep. There are many different definitions for chronic insomnia. A commonly accepted one is insomnia that occurs more than 3 nights a week for at least 3 months or that lasts for a month or longer.

Insomnia affects people in different ways. If you suffer from it, you may not be able to go to sleep or you may not be able to stay asleep. You might constantly wake up earlier than you would like, perhaps in the wee hours of the morning, and find yourself unable to go back to sleep.

Women are more likely to have insomnia than men. Possible risk factors may include:

• Shift workers, who don't have consistent sleep schedules
• Changes in sleep patterns and health with older age
• People who have a history of depression
• People who don't get much physical activity

Insomnia has many possible causes. They may include any or all of these:

• Medicines that interfere with sleep
• Dietary choices that interfere with sleep, such as having caffeine late in the day
• Stressful thoughts
• Depression
• Recent upheavals in your life, such as moving, job loss, divorce, or death of a loved one
• Hormone changes, such as those accompanying menstrual cycle, pregnancy, and menopause
• Bedtime habits that don't lead to restful sleep
• Sleep disorders, such as restless leg syndrome and sleep apnea
• Chronic pain
• Medical conditions, such as acid reflux, thyroid problems, stroke, or asthma
• Substances like alcohol and nicotine
• Travel, especially between time zones

These are common symptoms of insomnia:

• Frustration and preoccupation with your lack of sleep
• Physical aches and pains, such as headaches and stomachaches
• Impaired performance at work
• Daytime drowsiness or low energy
• Trouble paying attention
• Anxiety
• Tension and irritability
• Depression and mood swings

You may need to see a sleep medicine specialist to find out what's causing your insomnia. It will be helpful to bring a record of your sleep patterns.

The process of making a diagnosis may include:

• Your health history. Your doctor will consider any health conditions, medicines you're taking, and stressful life changes that could be causing insomnia.
• Your sleep history. Be prepared to describe your insomnia with details, such as how long it's been going on, what you think could be contributing to it, and what your sleep is like, such as whether you can barely get to sleep at all or if you wake up too early.
• Physical exam. The doctor will look for any physical reasons that could be causing sleep problems.
• Sleep study. You may need to sleep overnight in a sleep lab where researchers keep track of your sleep.

You have many choices for treatment:

• Change in lifestyle choices that may interfere with sleep
• Better sleep bedtime habits, called sleep hygiene
• Change in existing medicine, if that's what's causing the problem
• Counseling to help relieve stress and other issues bothering you
• Medicines to help you get to sleep and stay asleep. These are used with caution, especially for older adults

The exact course will depend on what your doctor identifies as the possible causes of your insomnia.

Insomnia can have serious complications. Poor sleep quality is linked to:

• Increased risk for heart disease
• Increased risk for stroke
• Increased risk for diabetes
• Excessive weight gain or obesity
• Depression
• Increased risk for injury to yourself or others, such as a car accident caused by driving while drowsy

Insomnia, the term for having trouble sleeping at night, is one of the most common sleep complaints. About 1 in 3 adults has bouts of insomnia that last a few days at a time. Women are more likely to have insomnia than men.

• Insomnia has many possible causes. You may need to see a sleep medicine specialist to find out what's causing your insomnia.
• Common symptoms of insomnia include impaired work performance, daytime drowsiness or low energy, difficulty paying attention, depression, and anxiety.
• Diagnosis may include a sleep study in which a sleep specialist keeps track of your sleep.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are and when they should be reported.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you don't take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours or on weekends and holidays.