This study tests a medicine called lumateperone for treating people with bipolar mania, which means having extreme "up" moods. Bipolar I disorder involves mood swings, including mania. The study lasts 5 weeks and has three parts: a 1-week screening phase, a 3-week treatment phase, and a 1-week follow-up. During treatment, participants will either get lumateperone or a placebo, which is a pill with no medicine, to see how well lumateperone works. Participants must be adults aged 18 to 75 who have been diagnosed with bipolar I disorder and are currently experiencing a manic episode. They must be able to give consent and should not have other psychiatric issues like schizophrenia or severe substance abuse, except nicotine.

• The study lasts for 5 weeks.
• You may need to take medicine or a placebo.
• You'll have several clinic visits for safety checks.

Eligible participants must be hospitalized for the current manic episode and score high on certain questionnaires measuring mania and mood. This study aims to find effective treatments for people experiencing bipolar mania.