Changes in Self-Reported Depressive Symptoms Among Adults in the United States From 2005 to 2016.

The PHQ-9 is a screening questionnaire, not a diagnostic interview, so the study cannot tell how many people had major depressive disorder. Depressive symptoms were self-reported, so answers may over- or under-report symptom frequency. NHANES is cross-sectional. It did not follow the same people over time, so it cannot show what caused the changes. The analysis excluded 3,772 adults with missing PHQ-9 answers, and the survey lacked PHQ-9 data for years immediately before and after the study interval. The sample was non-institutionalized civilian U.S. adults, and most were female, aged 18 to 60, non-Hispanic White, and without comorbidities, so results may not apply to institutionalized people. Low response rates to the suicidality item may have limited the ability to detect a significant increase in high scores for that item.

The article is listed as supported by NIH extramural research funding. Author DG reports a book royalty agreement with Taylor Francis Publishing. Author MS reports grant support from Otsuka, Alkermes, Janssen, NIH, CDC, and the International Society for Bipolar Disorders; consulting for Bracket, Otsuka, Janssen, Alkermes, Neurocrine, and Health Analytics; and royalties from Springer Press, Johns Hopkins University Press, Oxford Press, and UpToDate. All other authors report no conflicts.

Do not read this as proof that diagnosed depression increased or that screening or treatment caused the rise. The study used self-reported PHQ-9 scores without diagnostic assessment, and the cross-sectional survey design cannot follow the same people over time or establish cause.