"Resignation" is the twenty-second episode of the third season of House

House (TV series)

House is an American television medical drama that debuted on the Fox network on November 16, 2004. The show's central character is Dr. Gregory House , an unconventional and misanthropic medical genius who heads a team of diagnosticians at the fictional Princeton-Plainsboro Teaching Hospital in...

and the sixty-eighth episode overall.
Nineteen-year-old Addie (Lyndsy Fonseca

Lyndsy Fonseca

Lyndsy Marie Fonseca is an American actress known for playing Colleen Carlton on the CBS daytime soap opera The Young and The Restless, Dylan Mayfair on the ABC series Desperate Housewives, and Ted Mosby's daughter on How I Met Your Mother. She also played Katie Deauxma in the 2010 superhero film...

) coughs up blood during martial arts practice and her condition soon deteriorates. House surmises that her body is "confused" and thinks she has an infection, though none can be found. He clings to the diagnosis more stubbornly than usual, and behaves oddly in other ways, too.

House meanwhile notices that Wilson is yawning and recognizes it as a symptom of anti-depressant use.