Ben Stiller was diagnosed with prostate cancer in 2014, which he and his family kept a secret for two years. In a 2016 essay he wrote on Medium, Stiller then advocated the use of a controversial cancer screening, called PSA testing, for which he caught serious flack by detractors who claim the test gives too many "false positives, leading to dangerous, aggressive, and unnecessary treatment.
In the middle of Stiller's cancer battle, his beloved mother, Anne Meara, passed away on May 23, 2015. In an interview with Parade, Stiller said that his mom was the person he "most looked up to for her point of view, her humor," and that her death affects him constantly. Given the nature of Stiller's consistently gloomy demeanor, the one-two punch of a cancer diagnosis and the passing of his mother likely had a seriously negative effect on his marriage.