Carrie Mathison (Claire Danes)Brilliant, unstable and intense, Carrie Mathison (Claire Danes) is a CIA agent with the ability to crack cases and find clues where others cannot. Diagnosed with bipolar disorder, she struggles to regulate her mental health while still maintaining her razor sharp intuition. She has an older sister Maggie and two nieces, Ruby and Josie, who she adores. She is very close with her father Frank who also suffers from bipolar disorder.While a student studying Arabic at Princeton University, she was recruited into the CIA by her mentor Saul. Saul is somewhat of a father figure to Carrie and she relies on him to help her navigate the politics, rules and regulations of the CIA. She often clashes with her boss, CIA Director David Estes, with whom she has a rather strained relationship. In the past, David and Claire were romantically involved.While on assignment in Iraq, Carrie learns from one her assets that an American prisoner of war has been turned into an Al Qaeda operative. She is convinced that Sergeant Nicholas Brody is that prisoner of war and becomes obsessed with proving to everyone that Brody is a terrorist.Carrie often behaves erratically in the course of doing her job. She believes she is justified in her actions because the stakes of her job are so high.Background: Carrie was on assignment in Iraq for five years but was called back to Langley by David Estes when her unauthorized infiltration of an Iraqi prison caused an international incident.