The symptoms of depression vary from person to person, and the internet is inundated with anecdotes by self-diagnosed sufferers or falsehoods about the condition. To help remedy the flow of misinformation on the internet, Google and the National Alliance on Mental Illness (NAMI) will direct people who Google depression or depression-related symptoms to the PHQ-9 questionnaire, a standard tool used by doctors to diagnose depression.

Unlike the bevy of listicles or online quizzes that a person battling depression might find, the tool is clinically proven and should be able to help those who may not even realize they suffer from depression.

“People accommodate to their experience. The hope is that this will give people information they can reflect on,” says Kenneth Duckworth, the medical director at the National Alliance on Mental Illness. “Depression is common, and depression is treatable. With those two facts in mind we decided to do this partnership to advance public health. We believe information is power.”

Feeling down, poor concentration and diminished appetite are commonly known symptoms of depression, but some symptoms are more subtle, such as shifting sleep patterns or lower than normal energy levels.

While depression is a personal mental health issue, every person left undiagnosed or untreated from depression has a negative impact on society. A study published in the Journal of Social Psychiatry and Psychiatric Epidemiology estimates that depression costs the United States around $5,524 per working person per year, amounting to a 0.5% loss in total GDP.

According to numbers by the National Institute of Mental Health, 16 million adults (about 6.7% of adults) in the United States suffered one or more major depressive episodes within the last year—and of those diagnosed with major depression, only half receive care.

Google has provided a similar service to people with suicide-related searches since 2015. While such services can be safely considered a net good, big data has been used once before by internet ad agencies to target alcoholics with booze banners. 

Google Trends, which collects data on popular searches in a given geographic area, can be used to gauge which drugs are popular in certain parts of the country.