Insights Provided by Depression Screening Regarding Pain, Anxiety, and Substance use in a Veteran Population

Objective: We sought to quantify the extent to which a depression screening instrument commonly used in primary care settings provides additional information regarding pain interference symptoms, anxiety, and substance use. Methods: Veterans Aging Cohort Study (VACS) data collected from 2003 through 2015 was used to calculate odds ratios (OR) for associations between positive depression screening result cutoffs and clustering conditions. We assessed the test performance characteristics (likelihood ratio value, positive predictive value, and the percentage of individuals correctly classified) of a positive Patient Health Questionnaire (PHQ-9 & PHQ-2) depression screen for the identification of pain interference symptoms, anxiety, and substance use. Results: A total 7731 participants were included in the analyses. The median age was 50 years. The PHQ-9 threshold of ≥20 was strongly associated with pain interference symptoms (OR 21.6, 95% CI 17.5-26.7) and anxiety (OR 72.1, 95% CI 52.8-99.0) and yielded likelihood ratio values of 7.5 for pain interference symptoms and 21.8 for anxiety and positive predictive values (PPV) of 84% and 95%, respectively. A PHQ-9 score of ≥10 still showed significant associations with pain interference symptoms (OR 6.1, 95% CI 5.4-6.9) and symptoms of anxiety (OR 11.3, 95% CI 9.7-13.1) and yet yielded lower likelihood ratio values (4.36 & 8.24, respectively). The PHQ-9 was less strongly associated with various forms of substance use. Conclusion: Depression screening provides substantial additional information regarding the likelihood of pain interference symptoms and anxiety and should trigger diagnostic assessments for these other conditions.