To prepare for her role in the series, Claire Danes met with CIA officers. She also watched videos made by people with bipolar disorder and consulted with author Julie Fast who suffers from the same disorder.
Carrie's name was originally intended to be Claire. It was changed to Carrie when Claire Danes accepted the role.
Some viewers believed Claire Danes portrayal of a bipolar sufferer was too realistic to be acting and wrote to the broadcaster suggesting that she be given time off.
Season five made history for being the first U.S. TV series to shoot an entire season in Berlin, Germany.
Some of the photographs that are interspersed over the course of the opening credits sequence are actual pictures of Claire Danes as a young girl.