It's no secret that mental illness is a big problem for many people, and it is one of the leading causes of disability. A new report says that those who are considered "well" enough to work often struggle with anxiety or depression at work, slowing productivity.

According to Fox News, the Organization for Economic Cooperation and Development says that between 30 and 50 percent of new disability claims in OECD nations are due to mental illness or poor mental health.

In addition, the World Health Organization estimates that mental illness will be the second leading contributor to disease by the year 2020. While many common mental disorders can be treated and can get better, not everyone seeks treatment. In fact, one study says that 50 percent of people with severe mental illness do not seek treatment, and 70 percent of those with moderate mental health issues do not seek treatment, either.

Those who do work while struggling with depression or other mental issues often have to take sick days. Some worry for their jobs. The OECD report found that employment rates for people with a mental disorder are between 55 and 70 percent - much lower than the average for those without a disorder.

Many countries focus treatment on severe disorders like schizophrenia. That means less severe but more common disorders may go under the radar. The OECD says that taking such disorders more seriously would allow more people to return to work.

The organization also urged employers to help workers manage their stress and reduce workplace conflict.

Source: Fox News, "Poor mental health harming productivity, report says," Dec. 13, 2011