We've already mentioned the role of anosognosia in mental illness. The video below (7 min) was made by a man with bipolar disorder who after many years of denial was finally able to realize that he had a mental illnes. Ever since that "light bulb" moment he has contined to manage his condition with medication and therapy. He gives a first-person account of what anosognosia feels like, and he explains why attempting to convince a person who has a mental illness to get help can be such a struggle. It's not that they're being difficult. It's that despite all the evidence, they genuinely do not understand or realize that they have a mental illness. For more on anosognoia see the NAMI article.