Excessive sleepiness is exactly as the name implies: feeling the need to sleep during the daytime. It involves the difficulty of maintaining full awakeness and alertness during the day. It can be a symptom of many diseases, including many sleep disorders. Some examples of possible underlying conditions include but are not limited to irregular sleep-wake disorder, narcolepsy, Kleine-Levin syndrome, and idiopathic hypersomnia. Pharmacological treatments, as well as behavioral therapy, are available treatment options.