categorizes sleep disorders into 10 disorders or disorder groups, including: (1) insomnia disorder; (2) hypersomnolence disorder; (3) narcolepsy; (4)breathing-related sleep disorders; (5) circadian rhythm sleep-wake disorder; (6) non-rapid eye movement (NREM) sleep arousal disorder; (7)nightmare disorder; (8) rapid eve movement (REM) sleep behavior disorder; (9) restless legs syndrome; and (10) substance / medication-induced sleep disorder.