The PHQ-9 isn't any old test, so the Google result isn't like taking a Buzzfeed quiz about what kind of cocktail you are. It's one of the officially recognized tests for depressive diagnosis, and is used widely across the United States and UK, from the National Health Service to the Department of Defense. If you've been given an official depression diagnosis in either of these countries, chances are very strong that this is the test that was administered to you to help determine the severity of your symptoms.

It's also been found to be extremely accurate. In 2001, scientists tested it out on 6,000 patients across the United States, and found that scoring in the regions designated for "major depression" picked up the diagnosis 88 percent of the time, and that ranks on the scoring correlated pretty exactly to the severity of depression symptoms. They concluded that it's both "reliable and valid." The step that Google has taken is moving the PHQ-9 online and out of the doctor's office, and that may have been a good innovation.

Self-diagnosis isn't habitually seen as particularly useful for illness, but mood disorders are different. Self-reported mood issues are a key to diagnosis, and doctors can't assess their severity without the patient keeping a good record. As many of us don't actually record our moods or specific depressive symptoms day-to-day, particularly if we're not educated on depression or don't have a diagnosis, the PHQ-9 aims to fill in necessary gaps. And by making the PHQ-9 accessible before a depressive person decides to get help (when they're simply Googling symptoms), Google's initiative may create the push they need. And that's not a small matter.

A study of 50,000 people in 21 countries published in 2016 found that only one person in 27 people with depression gets any treatment for their condition at all. Particularly in countries where mental healthcare is difficult to get, but the internet is widely accessible, the PHQ-9's appearance in Google results might shift these statistics to allow for more and better treatment. But it's not just a problem in "other places." In the United States, the National Institute on Mental Health itself revealed in 2010, only 51 percent of people who meet the criteria for depressive disorder get treatment. Many of the people who took part in the 2010 research hadn't been diagnosed at all, and those who did often didn't meet any of the official guidelines set by the American Psychiatric Association for treatment. In that context, the availability of the PHQ-9 looks like a good idea.

Wariness about leaving diagnosis to Google, however, is a valid response. For one, the PHQ-9 is never meant to be a diagnostic tool on its own. It's meant to be administered by a physician who can also professionally determine other things that could be causing depressive symptoms besides depression itself, like bereavement or bipolar disorder. Context, when it comes to mood disorders, is very important: Depression is an extremely complex disorder, comprising genetic vulnerability, physical health, past traumas, stress, addiction issues, co-existing mental health problems, and a host of other different possible contributing factors. The existence of the PHQ-9 is just a number on a page; to be truly effective, it has to be paired with in-person work with a professional.

"Other co-morbidities may exist (e.g. anxiety disorders), and the depression may be due to central nervous system disorders, endocrine disorders (e.g. hypothyroidism), medication or other medical disorders," Harvard psychiatrist Srini Pillay, M.D., tells Bustle. "Ignoring this may lead to a medical disorder being untreated. The depression screening may be misleading in that people may believe that they have an 'emotional' problem and ignore the medical causes as well."

The difficulty with the PHQ-9 and its results, when not administered by a physician, is that people who obtain a major depressive score may attempt to treat it by themselves, with St. John's Wort, exercise or meditation — which is an excellent idea unless the depression itself is caused by underlying neurochemical factors that can't be diagnosed without a doctor.

"The PHQ-9 is certainly a relevant tool as it relates to depression," Pillay notes, "but there are a few things to bear in mind." For one, he explains, "while it may be helpful as a screening tool for depression, the interpretation can be more complicated in certain populations such as the coronary artery disease population. Also, it is a rough measure of depression severity and it is not a diagnostic instrument."

The other factor to consider is that the PHQ-9, while widely accepted, isn't the only measuring tool for depressive symptoms. Another is called the QIDS-SR (the Quick Inventory of Depressive Symptomatology, Self-Report), which covers much the same ground but in different ways and with an altered scoring system. And the World Health Organisation has something called a World Mental Health Composite International Diagnostic Interview, which is meant to be administered by a trained interviewer to diagnose many kinds of mental illness, including co-existing ones. The PHQ-9 isn't the only option out there, and depression is sufficiently diverse that it may prove inaccurate for a minority of patients who do actually need help.

"It is important to bear in mind that online self-diagnosis is a weak data point, and that the best way to establish whether one has a clinical depression is to visit a professional such as a psychiatrist, psychologist or primary care physician," Pillay tells Bustle. "The internet is a valuable adjunctive resource, and it may be useful to take one’s own findings in to that visit with a professional."

Overall, Google's work is moving in the right direction — but don't take it as a diagnosis without consulting a professional and getting all the information you can get. When it comes to mental health, you can never be too careful.