Your doctor often can determine the cause of your insomnia by asking about your habits and sleep environment, by reviewing your symptoms, and by examining you. Your doctor may suggest that you keep a sleep diary (a log of your sleep patterns) to provide an exact record of how many hours you sleep, whether symptoms may be your trigger for awakenings, and at what times you wake up.
If your doctor suspects that a medical illness is causing your insomnia, you may need additional tests. In some patients, an overnight sleep study at a sleep clinic may be necessary. During a sleep study, your brain waves, breathing pattern and oxygen levels can be monitored, and your body movements can be observed.