Microsleeps are often tied to diseases. Sleep apnea is by far the most significant disease tied to microsleeps in terms of prevalence, affecting roughly 10–15 million people. Other diseases that may be tied to microsleeps include narcolepsy, hypersomnia, schizophrenia, and other causes of excessive daytime sleepiness. Microsleep episodes are often neglected and are not used as a diagnostic indicator for these diseases. Instead, clinicians use instrumentation like PSG to do a sleep study on patients to assess overall sleep quality in a laboratory setting.