The study is designed to look at the usefulness and safety of pitolisant or placebo for the treatment of Idiopathic Hypersomnia. Idiopathic Hypersomnia (IH) is a sleep disorder in which a person is excessively sleepy during the day and has great difficulty being awakened from sleep. The study staff nor the participants will know if they are receiving the study drug or a placebo. Participants will be male or female 18 or older with a diagnosis of Idiopathic Hypersomnia (IH). The study treatment period from screening to follow-up will last approximately 16 weeks, requiring five visits and seven telephone calls.

The study is designed to look at the usefulness and safety of SUVN-G3031 or placebo for the treatment of excessive daytime sleepiness. Study staff nor the participants will know if they are receiving a study drug or placebo. Participants will be male or female subjects 18-50 years old with a diagnosis of narcolepsy. The study will last approximately 3 to 7 weeks with 5 visits for an individual subject. Study drug will be administered as a pill.

The study is designed to look at the usefulness and safety of AXS-12 or placebo for the treatment of Narcolepsy. The open-label treatment period is 24 weeks, which will be followed by a double-blind treatment period of 4 weeks, for a total of up to 28 weeks with 13 visits. Narcolepsy is a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep. Study staff nor the participants will know if they are receiving a study drug or placebo. Participants will be male or female subjects 15-75 years old with a diagnosis of narcolepsy. Study drug will be administered as a pill.

The study is designed to look at the usefulness and safety of AXS-12 or placebo for the treatment of Narcolepsy. Narcolepsy is a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep. Study staff nor the participants will know if they are receiving a study drug or placebo. Participants will be male or female subjects 15-75 years old with a diagnosis of narcolepsy. The study will last approximately 28 weeks with 8 visits for an individual subject. Study drug will be administered as a pill.