Ineffective treatment for anxiety disorders and depression is leading to significant economic problems and hinders human development, suggests new research from the World Health Organization.

Those mental health disorders cost the global economy $1 trillion every year, according to the study, which was published Tuesday in The Lancet Psychiatry. Furthermore, mental illnesses cause "a lot of death and a lot of disability," WHO's Dr. Shekhar Saxena told NPR.

From a health perspective, it has always made sense to treat these disorders, WHO Director-General Dr. Margaret Chan said in a statement, adding that "this new study confirms that it makes sound economic sense too."

The study estimated what would happen if more resources were dedicated to improving treatment for depression and anxiety in 36 low-, middle- and high-income countries between now and 2030.

Scaling up treatment, mainly psychosocial counseling and antidepressant medication, would cost a total of $147 billion in this time period.

The good news: Increasing treatment in this way would translate to a 5 percent improvement in labor force participation and productivity, which the study estimates would add $399 billion into the global economy. Plus, the research found such improvements to mental health treatments would result in people worldwide adding a combined 43 million healthy years to their lives by 2030 -- which would mean an additional $310 billion in returns.

"When it comes to mental health, all countries are developing countries," Saxena said, explaining that some high-income countries only average one psychiatrist for every 2,000 residents.

WHO currently has several programs in place to assess countries' mental health resources, and deploys trained professionals to assist people in emergency situations.