Study of Oral ABBV-932 to Assess Adverse Events and Change in Disease Activity in Adult Participants With Bipolar I or II Disorder

Bipolar disorder is a severe chronic mood disorder that affects up to 4% of the adult population in the United States. This study will assess how safe and effective ABBV-932 is in treating participants with bipolar I or II disorder. ABBV-932 is an investigational drug being developed for the treatment of depressive episodes in adult participants with bipolar I or II disorder. Study doctors put participants in 1 of 4 groups, called treatment arms. There is a 1 in 4 chance that a participant will be assigned to placebo. Around 160 adult participants with bipolar I or II disorder will be enrolled in approximately 40 sites worldwide. Participants will receive oral capsules of ABBV-932 or matching placebo once daily for 6 weeks. The treatment period will be followed by a safety follow-up (SFU) period for 4 weeks. There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular weekly visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects and completing questionnaires.

Inclusion Criteria: * Meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) criteria for bipolar I or II disorder without psychotic features based on the Mini International Neuropsychiatric Interview (MINI), with a current depressive episode of at least 4 weeks and not exceeding 12 months. * Have a minimum score of 20 on the 17-item Hamilton Depression Rating Scale (HAMD-17). * Have a minimum score of 2 on Item 1 of the HAMD-17 at screening. Exclusion Criteria: * Positive urine drug screen (UDS) result at screening. * Treated with any investigational drug within 4 weeks or 5 half-lives of the drug (whichever is longer) prior to the first dose of study drug, is currently enrolled in another clinical study, or was previously enrolled in this study. * Current use of any antipsychotic, antidepressant, anticonvulsant, mood stabilizer, herb, or over-the-counter medication with psychoactive potential within 1 week or 5 half-lives of the medication (whichever is longer). * Prior exposure to ABBV-932 within 90 days prior to baseline.