To compare the risk for mental illness of women with ovarian caner with that for women without cancer, investigators analyzed data from 1,689 patients with ovarian cancer diagnosed between 1996 and 2012 and a matched group of 7,038 women without cancer. Electronic health records were used to identify new mental health diagnoses following cancer diagnosis. Ovarian cancer survivors experienced increased risks for mental illnesses, particularly within the first 2 years after cancer diagnosis (hazard ratio [HR], 3.48), compared with the general population. Within the first 2 years after diagnosis, the risks for depression among ovarian cancer survivors were highest (HR, 3.11) and dropped for years 2-5 (HR, 1.67). Results were similar for the risk for anxiety disorder (years 0-2 HR, 3.54; years 2-5 HR, 1.86). The risk for adjustment disorders also was elevated in women diagnosed with ovarian cancer compared with women in the general population. Among patients with ovarian cancer, those who received a mental health diagnosis (HR, 1.8) or a depression diagnosis (HR, 1.94) were more likely to die compared with those without a mental health diagnosis.