Doctors Answers (2)
Excessive Daytime Sleepiness can be caused by poor sleep at night. That could include any variety of sleep disorders or causes that are disrupting your sleep. Medications can sometimes cause sleepiness during the day. It is not possible to thoroughly determine Narcolepsy without first ruling out nighttime disorders.
Daytime sleepiness may be caused by any sleep disorder or issue which either fragments the sleep or reduces the amount of sleep needed. This is sleep deprivation. Generally, when the reason for the sleep deprivation is eliminated, the person is not excessively sleepy the next day. A newborn baby, school work, partying, anything can cause this. Other causes for daytime sleepiness would include medication effect and, as you mentioned, narcolepsy. Narcolepsy may be an autoimmune disorder and possibly your arthritis and thyroid disorders may also be autoimmune in nature. It should not take a board certified sleep specialist very long to come up with an answer as to why you are sleepy. Treatment is available to improve your quality of life and to insure your safety and the safety of others.