Depression, anxiety disorders, and bipolar disorder are chronic and highly disabling conditions that start early in life and often continue for a significant period, resulting in huge economic and health losses. Here, we make a compelling argument for scaled-up investments in mental health to address the losses from depression, anxiety disorders, and bipolar disorder. We used the mental health module of the OneHealth tool to calculate treatment costs and health impacts from 2022 to 2042. We assumed a linear increase in treatment coverage.