Reliability and validity of the Patient Health Questionnaire-4 scale and its subscales of depression and anxiety among US adults based on nativity

The burdens of anxiety and depression symptoms have significantly increased in the general US population, especially during this COVID-19 epidemiological crisis. The first step in an effective treatment for anxiety and depression disorders is screening. The Patient Health Questionnaire-4 (PHQ-4, a 4-item measure of anxiety/depression) and its subscales (PHQ-2 [a 2-item measure of depression] and Generalized Anxiety Disorder [GAD-2, a 2-item measure of anxiety]) are brief but effective mass screening instruments for anxiety and depression symptoms in general populations. However, little to no study examined the psychometric properties (i.e., reliability and validity) of the PHQ-4 and its subscales (PHQ-2 and GAD-2) in the general US adult population or based on US nativity (i.e., foreign-born vs. the US-born). We evaluated the psychometric properties of the PHQ-4 and its subscales in US adults, as well as the psychometric equivalence of the PHQ-4 scale based on nativity.

We conducted a cross-sectional survey of 5,140 adults aged ≥ 18 years. We examined the factorial validity and dimensionality of the PHQ-4 with confirmatory factor analysis (CFA). A multiple-group confirmatory factor analysis (MCFA) was used to evaluate the comparability of the PHQ-4 across nativity groups. Reliability indices were assessed. Also, the scales’ construct validities were assessed by examining the associations of both the PHQ-4 and its subscales’ scores with the sociodemographic characteristics and the 3-item UCLA Loneliness scale.

The internal consistencies were high for the PHQ-4 scale (α = 0.92) and its subscales of PHQ-2 (α = 0.86) and GAD-2 (α = 0.90). The CFA fit indices showed evidence for the two-factor structure of the PHQ-4. The two factors (i.e., anxiety and depression) were significantly correlated (r = 0.92). The MCFA demonstrated measurement invariance of the PHQ-4 across the nativity groups, but the model fits the data better in the foreign-born group. There were significant associations of the PHQ-4 scale and its subscales’ scores with the sociodemographic characteristics and the UCLA Loneliness scale (all p < 0.001).

The PHQ-4 and its subscales are reliable and valid measures to screen anxiety and depression symptoms in the general US adult population, especially in foreign-born individuals during the COVID-19 pandemic.