When excessive daytime sleepiness is confirmed, on the basis of clinical assessment and sleep testing, it is often found to have an underlying cause (see EDS). Sometimes no cause is found for a person's obvious sleepiness. In such cases, the diagnosis of Idiopathic Hypersomnia is often appropriate.
Despite the lack of an underlying explanation, treatment does exist in the form of medicines to increase the level of alertness during the day. These are frequently effective and generally well tolerated.