This study is testing a new medicine, brenipatide, for adults with bipolar disorder. Bipolar disorder is a mental health condition that causes extreme mood swings. The study checks if brenipatide, given with usual treatment, helps delay worsening symptoms compared to a placebo (a pill that looks like medicine but isn't). First, there's a screening period for about a month to check if participants are eligible. Then, participants will receive treatment for at least 6 months. A follow-up will happen for about 2 months.

• Participants need to be available for all visits and follow instructions, including self-injections.
• The study lasts several months but can be shorter if symptoms worsen or if the participant leaves.
• Participants must not have other serious mental health issues, certain physical health issues, or substance use problems.

Before joining, ensure you can commit to the time and tasks. If you have any conditions listed in the exclusion criteria, you may not be eligible to participate.