The U.S. is one of the most depressed countries in the world, according to the World Health Organization.

In terms of quality years of life lost due to disability or death – a widely adopted public health metric that measures the overall burden of disease – the U.S. ranked third for unipolar depressive disorders, just after China, which ranked No. 1, and India.

[Read about the challenges in collecting disability data.]

India, China and the U.S. are also the countries most affected by anxiety, schizophrenia and bipolar disorder, according to WHO.

About one in five adults in the U.S. experiences some form of mental illness each year, according to the National Alliance on Mental Illness , but only 41 percent of those affected received mental health care or services in the past year.

In August of 2016, then-presidential candidate Hillary Clinton released a plan to reform the mental health system in the U.S., a favorable step for advocates who have cited issues such as an insufficient number of providers and the expensive costs of medication.

Closing the gap between mental health patients and providers is a global issue.

"In 2014, 45 percent of the world's population lived in a country where there was less than one psychiatrist to serve 100,000 people," according to WHO .

Asia has an especially low concentration of psychiatrists. Europe has the highest, led by Monaco, Norway, Belgium and the Netherlands, each with between 20 and 40 psychiatrists per 100,000 people. The U.S. and Canada have about 13 psychiatrists per 100,000 people, according to WHO.

Here are the countries with the greatest burden of disease for mental and behavioral disorders, in terms of most years of life lost due to disability or death adjusted for population size, according to WHO.

