Tests and diagnosis
In addition to asking you a number of questions, your doctor may have you complete a questionnaire to determine your sleep-wake pattern and your level of daytime sleepiness. You may also be asked to keep a sleep diary for a couple of weeks if you haven't already done so.
Your doctor will likely do a physical exam to look for signs of other problems that may be causing insomnia. Occasionally, a blood test may be done to check for thyroid problems or other conditions that can cause insomnia.
If the cause of your insomnia isn't clear, or you have signs of another sleep disorder, such as sleep apnea or restless legs syndrome, you may need to spend a night at a sleep center. Tests are done to monitor and record a variety of body activities while you sleep, including brain waves, breathing, heartbeat, eye movements and body movements.