In Salinger's book, The Catcher In the Rye, Holden Caulfield experiences depression through the symptoms of physical ailment and thoughts of suicide. Holden's sickness is unexplained in some parts of the book without a cause, such as at Mr. Antonili's. His thoughts of suicide are spread throughout the entire book and a major reason I believe Holden is facing depression. He thinks about suicide after being beaten up by Maurice. Most likely these symptoms are because of Allie's death which has caused him to be depressed.
National Institute of Mental Health. "Depression." National Institutes of Health, Oct. 2016, http://www.nimh.nih.gov/health/topics/depression/index.shtml. Accessed 07 Feb. 2017.
Salinger, J. D., E. Michael Mitchell, and Lotte Jacobi. The Catcher in the Rye. Boston: Little, Brown, 1951. Print.