Could it be bad not to have treatment for bipolar disorder?

Yes. : Untreated bipolar disorder can be very devastating as it can affect all ares of one's functioning, including relationships, jobs, and physical health.

19% commit suicide: The answer is a clear yes. Bipolar disorder is a very serious, potentially fatal illness, much like cancer. In spite of decades of research, some people still find it difficult to understand that bipolar disorder requires a life long treatment regimen, which includes medications and therapy. Think of it more like sickle cell anemia or diabetes, which require care from a specialist.