Someone i know lying about bi-polar disorder?

This depends on who : they are in your life. If its your teacher, they may be lying. If its someone who can tell you and feel ok about it, let them know you are there for them and want to help. Make it clear you asking to help and will value and guard their privacy. Bipolar is very common and undertreated as many patients dont like medicine or the idea of being on it, until they see how unmanageable their lives are wit