Kids will always push the boundaries to see how far they can go. Part of this is the process of independence but sometimes it is just seeing what they can get away with. The biggest and most important thing with kids is to be consistent. The rules need to stay the same regardless of how tired mom or dad is, or how busy life gets. With all of this said and the question you posed....
How would you relate to a child who grows up with a parent with mental illness? Are these boundary issues the same? Why or Why not?