Final answer:
The 2009 Tony Award-winning musical about a mother's battle with bipolar disorder is 'Next to Normal'. It's known for its earnest depiction of mental health.
Step-by-step explanation:
The 2009 Tony Award-winning musical that addresses a mother's struggle with bipolar disorder and its impact on her family is Next to Normal. This compelling and groundbreaking musical dives deep into the complexities of mental health and familial dynamics, setting itself apart from other musicals of the time with its raw and insightful portrayal of a stigmatized issue. Unlike other satirical and humorous musicals like Avenue Q and Spamalot, or the culturally rich In the Heights, Next to Normal offers a poignant and serious exploration of real-life challenges, making it a notable entry in the canon of modern American musical theatre.