When “Bothered by” Means “Often”: Evidence for Misinterpretation of the Patient Health Questionnaire

Importance: Versions of the Patient Health Questionnaire such as PHQ-2, PHQ-8, and PHQ-9 are among the leading assessment tools for depression in research and clinical practice. However, important questions remain about its validity, particularly whether responses reflect symptom frequency or the degree to which symptoms are bothersome.Objective: To investigate how participants respond to the PHQ, described as a “severity” measure by its developers, with instructions about “being bothered by symptoms”, and response options focused on symptom “frequency”.Design, Setting, and Participants: The study used data from a general population sample collected via MTurk (N=503, Mage=40.63, SD=13.62; Male=253, Female=245, Transgender=3, Other=2) and a clinical sample with medium to high depression from the OPTIMA study (N=349, Mage=33.44, SD=12.23; Male=120, Female=216, Transgender=5, Other=8). Data were collected between 2022-2023.Main Outcome(s) and Measure(s): After completing the PHQ-8, participants’ interpretation of instructions was assessed via three questions: 1) How they would respond to the PHQ sleep item in a hypothetical scenario where they overslept nearly every day but were comfortable with oversleeping; 2) Whether they had based their earlier PHQ responses on symptom frequency, being bothered by symptoms, or both; 3) How they would answer the PHQ in the future, based on these same three options.Results: In the hypothetical oversleeping scenario, only 54.7% (n=275; MTurk) and 15.5% (n=53; OPTIMA) of participants interpreted the PHQ as instructed (i.e., the frequency with which the problems bothered them). When asked how they had responded to the PHQ, only 21.3% (n=107) and 11.7% (n=40) of participants interpreted the instructions as instructed, and only 22.3% (n=112) and 9.9% (n=34) reported they would do so in the future, indicating stability in their interpretation. The current study also found that the PHQ-8 validity varies depending on how participants interpret its instructions. Conclusions and Relevance: Our findings identify widespread misinterpretation of the PHQ instructions across community and clinical samples, raising doubts about its validity for both research and clinical decision-making. Keywords: PHQ, depression, assessment, validity