There is a short window in which insurance companies can investigate and deny potentially fraudulent claims.
The period is two years in most states and one year in others, and it begins as soon as a policy goes into effect. The most important thing you can do when applying for life insurance is to be honest.
The rule of thumb is that if you tell the truth on the application you can rest assured knowing your family will receive the death benefit at the time of your passing.
Suicide is not covered in the first two years of any life insurance policy sold in the U.S.