Lincoln's depression is well documented. It has been glossed over or minimized by American historians, always ready to keep America's historical figures in freshly-washed robes of white.
Truly critical looks at his symptoms actually point to something more serious than mere conventional depression.
There are at least two candidates for his condition: Marfan Syndrome or, something worse, Multiple Endocrine Neoplasia Type 2b.
By the way, his wife Mary almost certainly suffered from a moderate case of schizophrenia. Her symptoms are classic, and her strange behaviors often made Lincoln miserable and embarrassed.
That's why her son kept her institutionalized the last part of her life. Of course, the popular interpretation was that she was so miserable after husband's terrible death.
