In November 2000, Gambini (plaintiff) began working at DaVita, a dialysis center, which was owned by Total Renal Care, Inc. (DaVita) (defendant). Several months later Gambini, who had a prior history of medical problems, began suffering from depression and anxiety. In April 2001, Gambini had an emotional breakdown at work. A mental-health professional told Gambini her symptoms indicated bipolar disorder. Gambini began seeking medical treatment and taking medication to control her mood swings. Gambini returned to work, where she informed two supervisors and other coworkers about her condition and ongoing treatment. A year later, Gambini’s bipolar symptoms—including emotional outbursts, unpredictability, irritableness, distraction, and difficulty focusing on job tasks—grew worse. Gambini’s supervisors met to discuss this behavior and ultimately decided to draft a performance-improvement plan for Gambini. When they met with Gambini to give her the plan, Gambini began crying, shaking, and experiencing shortness of breath. Gambini threw the plan across a desk, used profane language, and slammed the door as she left. Gambini was fired several days later. She then wrote a letter to DaVita explaining that her volatile behavior at the meeting was due to her bipolar disorder and asking to be reinstated. When her request was refused, Gambini sued DaVita for disability discrimination under the Americans with Disabilities Act (ADA), 42 U.S.C. § 12101 et seq. The district court denied Gambini’s request for a jury instruction that “conduct resulting from a disability is part of the disability and not a separate basis for termination.” The district court granted summary judgment for DaVita. Gambini appealed.