People in the U.S. who type "clinical depression" in Google search via a mobile device will now be invited to check if they are clinically depressed via a screening questionnaire.

Google has teamed up with a mental illness group to provide Americans with a test to check if you are depressed or mentally ill.

The partnership, announced Wednesday, has been developed by Google and the National Alliance on Mental Illness (NAMI).

In a blog post on Google, the CEO of NAMI Mary Giliberti, said she wanted to use Google to increase the proportion of U.S. citizens who actually seek help for depression.

"Clinical depression is a very common condition, in fact, approximately one in five Americans experience an episode in their lifetime.

"However, despite its prevalence, only about 50 percent of people who suffer from depression actually receive treatment," Gilberti said.

Google said those who click through from the search suggestion will see a "Knowledge Panel" which will give you an option to "check if you are clinically depressed".

The test, called a PHQ-9, is described by the search engine as a clinically validated screening questionnaire and is designed to test what level of depression a person may be suffering.

Giliberti said the results can help people then have a more informed conversation with their doctor.

"Clinical depression is a treatable condition which can impact many aspects of a person's life. The PHQ-9 can be the first step to getting a proper diagnosis," Giliberti added.

The NAMI CEO said people who have symptoms of depression experience an average of a 6 to 8-year delay in getting treatment following the onset of symptoms.