From the World Health Organziation:
Depression and anxiety disorders are common mental disorders that have an impact on our ability to work, and to work productively. Globally, more than 300 million people suffer from depression, the leading cause of disability. More than 260 million are living with anxiety disorders. Many of these people live with both. A recent WHO-led study estimates that depression and anxiety disorders cost the global economy US$ 1 trillion each year in lost productivity.
Mental health in the workplace is the theme of World Mental Health Day 2017. World Mental Health Day is observed on 10 October every year, with the overall objective of raising awareness of mental health issues and mobilizing efforts in support of better mental health. (WHO, 2017)
For more on World Mental Health Day: