A new study calls into question the validity of the Patient Health Questionnaire (PHQ), a foremost depression screening tool, and cautions researchers and mental health providers about relying on PHQ results.
A new research report suggests that a widely used depression screening questionnaire should not be relied on for research purposes or in assessments for depression.
A team of academic researchers investigated the validity of the Patient Health Questionnaire (PHQ), whose various versions are among the most widely used tools in research and clinical settings worldwide for assessing depression in patients. The researchers’ particular concern was whether responses to PHQ questions reflected how often potential symptoms of depression were experienced, or how much those symptoms bothered the individuals. The PHQ instructions ask for how often the symptoms bother the person.
The study’s findings, reported in JAMA Psychiatry, indicated that fewer than one in five responded to the PHQ according to the instructions (i.e., how much the symptoms bothered them). Instead, their answers more often reflected the frequency, not severity of symptoms. The scoring resulting from those responses likely indicated more severe depression than was actually the case.
“Results of this study suggest that the PHQ is widely misinterpreted, raising concerns about its validity for research and clinical decision-making,” the report says.
Conditions the PHQ asks about – such as having “little interest or pleasure in doing things,” “feeling down,” “feeling tired or having little energy,” and “poor appetite or overeating” – may be felt by many people in the normal course of living.
Questions about such conditions, along with the misinterpretation of the PHQ instructions, likely result in the overdiagnosis of depression, as well as the overprescribing of antidepressants and other psychiatric treatment. It should be noted that the PHQ was developed in the mid-1990s with funding from Pfizer, an antidepressants manufacturer, which still holds the copyright for the questionnaire.
An analysis of data from the most recent National Health Interview Survey indicates a steady increase in antidepressant use from 2019 to 2023. Overall, antidepressant use increased from one in 10 Americans (9.8%) in 2019 to one in nine (11.4%) in 2023. The use of the PHQ by doctors to screen for depression during routine primary care, as now recommended by the U.S. Preventative Services Task Force (USPSTF), may well have contributed to that increase.
The National Institute for Health and Care Excellence in England and the United Kingdom National Screening Committee do not recommend routine screening of adults for depression. Neither does The Canadian Task Force on Preventive Health Care, after concluding that research studies provide only “very low-certainty evidence” to support the practice.
In contrast, the USPSTF recommends the screening, based on what it claims is a “moderate certainty that screening for depression has a moderate net benefit.” Even so, it advised health care providers to consider individual patient circumstances, such as an absence of any sign that the individual is depressed, before deciding whether to screen.
Overly assessing depression can have a ripple effect, leading to inflated reports of a mental health crisis in the U.S. and fueling calls for increased funding for mental health programs.
A recent Gallup poll asked respondents, “Has a doctor or nurse ever told you that you have depression?” Since doctors and nurses may tell patients they have depression based on questionable results from the PHQ, those patients’ replies when polled only reflect what they’ve been told, but do not reliably represent an actual rate of depression.
Beyond adults, research has also indicated that screening teens for depression does not reduce suicidal behavior, undermining the primary rationale for screening them, but may lead to overdiagnosing and overtreatment with antidepressants.
Antidepressants carry known risks of dangerous side effects. Psychiatrist Peter Breggin, M.D., describes antidepressants as neurotoxic, saying they harm and disrupt the functions of the brain and can cause abnormal thinking and behaviors that include anxiety, irritability, hostility, aggressiveness, loss of judgment, impulsivity, and mania, which can lead to violence and suicide.
The newly released documentary from the Citizens Commission on Human Rights, “Prescription for Violence: Psychiatry’s Deadly Side Effects,” is an exposé of the link between psychiatric drugs and violence, as well as the corruption and greed of the psychiatric industry fueling this crisis. The documentary can be viewed online here.
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Anyone wishing to discontinue or change the dose of an antidepressant or other psychiatric drug is cautioned to do so only under the supervision of a physician because of potentially dangerous withdrawal symptoms or other complications.