Yes, this is serious.
What I don't understand is why Bipolar is singled out. On all the applications I have seen to fill out, it specifically asks about Bipolar Disorder - but it does not ask if you have ever attempted suicide for any reason, it does not ask if you have Depression, Borderline Personality Disorder, Schizophrenia, or other disorders that have high suicide rates. Only Bipolar. Why is that? It's just not fair. People with depression commit suicide just as much as people with Bipolar, yet you still give them life insurance.
Suicide is not necessarily intentional. It is a complication of a disease - not a choice. When you get to that point, you are not thinking clearly. Your mind takes over. The illness takes over. It is not any different than a heart attack - only it's the brain that kills you, not the heart. You may view it as a choice, but that is not always the case.
Every application will ask about other mental and nervous disorders, which all of the things you just mentioned would fall into.....and most applications will usually ask if there are any other diseases or disorders diagnosed or treated that were not necessarily mentioned specifically in the medical questions. I'm not sure where you're getting your information from.
Just because you have bipolar disorder doesn't mean you'll be declined. We just got an offer back yesterday for a bipolar individual taking lithium and a couple other health issues for standard rates on his term insurance. When you combine bipolar with a history of multiple suicide attempts, that doesn't look very good from an insurance company's point of view. Would you insure someone for $1 million for under $1000 per year that has a history of suicide attempts, and within the past year no less?