The statistics are startling: about one-third of American workers suffer from chronic work stress; $27 billion worth of work days are lost to mental health-related absences each year. Harvard Business School professor John Quelch discusses his case — entitled “Mental Health in the American Workplace” — on the state of mental health in the U.S. workplace, and why even though companies are better than ever about providing services to their workers, the stigma attached to mental health leaves a lot of work yet to be done.