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  • Various Authors

PHQ-9 : Doctor Google is helping to diagnose depression online

Google is once again making its products available to benefit healthcare, this time mental health. users based in the US who make depression-related queries on the search engine will receive the prompt: "Check if you’re clinically depressed,” and be invited to fill out a screening questionnaire.

The clinically-validated questionnaire, called PHQ-9, is a private self-assessment that will provide a score indicating the severity of the user’s depression. Google says the information will not be recorded or shared. Rather, the goal is for the results of the test to be shared with the user’s doctor to inform further conversations about diagnosis and treatment.

PHQ-9 - Validity of a Brief Depression Severity Measure

The Patient Health Questionnaire (PHQ) is a self-administered version of the PRIME-MD diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores each of the 9 DSM-IV criteria as “0” (not at all) to “3” (nearly every day). The PHQ-9 was completed by 6,000 patients in 8 primary care clinics and 7 obstetrics-gynecology clinics. Construct validity was assessed using the 20-item Short-Form General Health Survey, self-reported sick days and clinic visits, and symptom-related difficulty. Criterion validity was assessed against an independent structured mental health professional (MHP) interview in a sample of 580 patients.

As PHQ-9 depression severity increased, there was a substantial decrease in functional status on all 6 SF-20 subscales. Also, symptom-related difficulty, sick days, and health care utilization increased. Using the MHP reinterview as the criterion standard, a PHQ-9 score ≥10 had a sensitivity of 88% and a specificity of 88% for major depression. PHQ-9 scores of 5, 10, 15, and 20 represented mild, moderate, moderately severe, and severe depression, respectively. Results were similar in the primary care and obstetrics-gynecology samples.

National Alliance on Mental Illness (NAMI)

According to the National Alliance on Mental Illness (NAMI), one in five Americans experience depression in their lifetime, but less than half seek treatment. Google told the Financial Times that one in 20 searches are related to health (it did not disclose the percentage that are depression-related). The search giant has been working NAMI since the start of the year to provide better and more reliable health information.

The depression screening questionnaire is the latest in a series of health-related developments for the Internet giant. Google previously launched a location-specific pollen counter, a BMI calculator, and provides a box of verified information called the “knowledge panel” containing symptoms and treatments for a number of common conditions, including the flu, tonsillitis, and headaches.

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