Flawed research methods exaggerate the prevalence of depression

The common practice of using patient self-report screening questionnaires rather than diagnostic interviews conducted by researchers has resulted in overestimates of the prevalence of depression, according to an analysis in CMAJ (Canadian Medical Association Journal).

"These studies misrepresent the actual rate of depression, sometimes dramatically, which makes it very difficult to direct the right resources to problems faced by patients," said Dr. Brett Thombs of the Lady Davis Institute of the Jewish General Hospital and McGill University, the study's lead author. "Self-report questionnaires are meant to be used as an initial assessment to cast a wide net and identify people who may be struggling with mental health issues. However, we need to conduct a more thorough evaluation in order to determine an appropriate diagnosis and whether there may be other issues to address."

The authors suggest that researchers often use self-report questionnaires because diagnostic interviews are time-consuming and expensive to administer.

"In addition," said Thombs, "Studies with dramatic results tend to be accepted by higher impact journals and attract more attention from the public than studies with more modest findings. This may also encourage some researchers to report results from questionnaires rather than conducting appropriate diagnostic interviews."

"Addressing overestimation of the prevalence of depression based on self-report screening questionnaires" is published January 15, 2018.