- Has insomnia related to restless leg syndrome (RLS) (defined as periodic leg movement [PLM]-arousal index of >=10 PLM-related electroencephalograph (EEG) arousals per hour of sleep for adult participants or >15 for elderly participants), sleep breathing disorder (defined as an apnea hypopnea index >=10 cumulative apneas and hypopneas per hour of EEG sleep for adult participants or >15 for elderly participants), or parasomnias. These disorders will be ruled out by the first PSG recording during Part 2 of screening