Depression Screening Tool Validates Accuracy for People with Chronic Pain

A new study has confirmed that the Patient Health Questionnaire-8 (PHQ-8), a widely used depression screening tool, accurately identifies depression in individuals with and without chronic pain, dispelling a long-standing concern that chronic pain might skew results. The findings, published in the *Journal of Affective Disorders*, address a critical gap in mental health care for patients with overlapping conditions.

The research, led by Jennifer S. De La Rosa, strategy director at the University of Arizona Comprehensive Center for Pain and Addiction, analyzed data from 31,983 U.S. adults participating in the 2019 National Health Interview Survey. Using advanced data science techniques, the team evaluated the PHQ-8’s measurement invariance, ensuring the tool’s reliability across groups with and without chronic pain. The results showed no significant differences in score consistency between the two populations.

Debunking a Misconception

Some clinicians had questioned whether chronic pain symptoms—such as fatigue or sleep disturbances—might artificially inflate PHQ-8 scores, as these symptoms overlap with depression. “Could pain symptoms artificially inflate depression screening scores among those with chronic pain? It’s a reasonable question, but it had not yet been definitively answered,” De La Rosa said. The study’s findings refute this concern, emphasizing that the PHQ-8 remains a valid tool for all patients.

“Clinicians need to know that a positive depression screening is just as reliable in their patients with chronic pain as patients without chronic pain,” De La Rosa added. She stressed the importance of offering mental health support to patients with unmet needs, regardless of their pain status.

Chronic Pain and Mental Health

The study underscores the complex relationship between chronic pain and depression. De La Rosa’s prior research found that 1 in 5 people with chronic pain also experience depression, while over half of those with clinically significant depressive symptoms have chronic pain. A follow-up paper revealed that adults with chronic pain are more likely to face anxiety and depression but are less likely to access mental health care.

“People with chronic pain are, in fact, the most typical patients living with unmet mental health needs,” De La Rosa said. She highlighted that this population is disproportionately represented among individuals with treatment-resistant depression, despite their willingness to participate in clinical trials. “Including them in research would improve the real-world effectiveness of new therapies,” she noted.

Implications for Research and Policy

The findings call for broader inclusion of chronic pain patients in depression studies. Currently, many clinical trials exclude individuals with chronic pain, limiting the applicability of results. “This study provides robust evidence that there would be no scientific problem with including folks living with chronic pain in depression research,” De La Rosa said.

The Centers for Disease Control and Prevention estimates that 64 million U.S. adults experienced chronic pain in 2023. Despite this, mental health care access remains uneven. De La Rosa urged policymakers and researchers to prioritize the needs of this underserved group. “Now is the time to meaningfully consider the unmet mental health needs of people with chronic pain and prioritize their outcomes within the mental health research, policy, and advocacy landscape,” she said.

Methodology and Funding

The study’s analysis relied on nationally representative data from the 2019 National Health Interview Survey, ensuring broad applicability. Researchers employed sophisticated statistical methods to assess potential biases in the PHQ-8. The work received support from the National Institutes of Health and involved collaborators from the University of Arizona, Arizona State University, and Johns Hopkins School of Medicine.

“This research highlights the importance of equitable access to mental health care and the need for inclusive clinical studies,” said De La Rosa. The study’s conclusions provide a foundation for revising guidelines and improving care for patients with comorbid chronic pain and depression.