Insomnia Diagnosis

Written by the Healthline Editorial Team | Published on October 13, 2014
Medically Reviewed by Kenneth R. Hirsch, MD on October 13, 2014

Insomnia Diagnosis

Your doctor will ask you an array of questions to diagnose your sleeping troubles. What are your sleep patterns? How long does it take you to fall asleep at night? Do you wake up well rested? How much do you exercise? Do you drink? Smoke? There are many different factors that can affect your ability to sleep.

Your doctor will perform a physical exam and take notes about your medical history. If none of this information sheds light on your sleep problems, your doctor may order blood tests to check the health of your thyroid gland. Insomnia is a common symptom of thyroid disease.

Sleep Diary

You may also be asked to keep a sleep diary. In it you should log your:

  • periods of sleep
  • food intake
  • medications
  • smoking
  • alcohol use
  • exercise

You will need to record everything for a couple of weeks. If you have a partner, your doctor may want to interview them to gather information about any snoring or restlessness during your sleep.

Sleep Testing


If the sleep diary doesn’t reveal the cause of your insomnia, your doctor may decide you need sleep testing. The most common sleep test is called a polysomnography. Sleep tests are performed at a sleep clinic. You will likely need to stay at the clinic overnight.

You will wear painless patches on different areas of your body during the test. The patches are linked by wires to monitoring equipment. As you sleep, the clinic staff will monitor your brain waves, breathing, and heartbeat. They will also record your oxygen levels and any eye and body movements. 

Multiple Sleep Latency Test

Another test is performed at a sleep clinic during the day. This is a multiple sleep latency test (MSLT). It measures your level of sleepiness during the day, how long it takes you to doze off, and what levels of sleep you experience. You will be monitored over the course of a day to record when you are the sleepiest.


You may also need an actigraphy. This uses a portable device that you wear on your wrist. It measures the time of day and level of your activities. The actigraphy can reveal if your circadian rhythm is off. This is your internal clock that sets your sleep and wake cycles. Shift work and travel can cause problems with your circadian rhythm and result in insomnia.

Sleep testing will help your doctor identify any sleep disorders you may have that are causing your insomnia. 

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