Brexpiprazole is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions). It is also used with an antidepressant to treat depression when symptoms cannot be controlled by the antidepressant alone. Brexpiprazole is in a class of medications called atypical antipsychotics. It works by changing the activity of certain natural substances in the brain.