There have been issues where people gone depressed and suicidal after watching Avatar. The link above is an article about this issue.
After watching Avatar people went depressed due to the fact that the world of Pandora is beautiful and perfect, compare to the world in reality. Where its polluted and people are killing it even more. However some people have taken this film too seriously, as they reached the point where they truly want to or believe in the fact that world Pandora exist and how they wish they are there.
In a way our world once was, beautiful and creative in a different way. But now its covered in technology and polluted like crazy. From things human have done, such as from selfish human beings too scientist who try to make living better for humans or save the world, through technology.
But to those who thinks that people who went suicidal is crazy and don't believe it, they should think again and their is countless of forum for people to communicate to each other, around the world,about which part made them suicidal and how they currently feel about the situation. To an extent, this issue was also on the news before, when the film was released not long.
The link below is a link to one of the many forums, however to view most things you have to be a member.