Does violence in movies have a bad effect on viewers?

The Hollywood actor Jim Carey is staring in the superhero film sequel, Kickass 2, which is set to be one of this summer's blockbusters.

However, Mr Carey has said that he can't back Kickass 2 anymore because it's "simply too violent". He says that he has withdrawn his support following the Sandy Hook massacre in Newtown, Connecticut, where 20 children were killed by a gunman last December.

The film's writer has said that he is "baffled" by the decision, and has urged Carey to reconsider.

But how fair is it to link film storylines with horrific events that have taken place in real life? Film maker and writer Adam Hamdy, and film critic Jason Solomons spoke with BBC Breakfast's Charlie Stayt and Susanna Reid about the issue of violence in films.