Measuring depression with questions about well-being: a study on psychiatric outpatients

Most depression rating scales are characterized by negatively-phrased questions, exploring the presence of various symptoms. Questions such as those regarding suicidal ideation or painful experiences may reduce accept-ability or even lead the reader to withdraw participation in the study. Although positively-worded items may be useful, it should be acknowledged that without formal testing they cannot be assumed to be equivalent to negatively-worded ones. The aim of the present study was to test the reliability and validity of a depression rating scale including only positively-phrased items.

Two groups were enrolled in the study: the first comprised 104 adult psychiatric outpatients, the second 88 undergraduate students. All participants completed the depression scale of the Patient Health Questionnaire, the Zung Self-Rating Depression Scale, and the Positively-phrased Depression Scale (PDS), a 10-item self-report instrument in which the items are phrased in a positive way to reflect the absence of symptoms. Psychiatric outpatients also were rated by their clinician on the Hamilton Depression Rating Scale.

The internal consistency of the PDS was satisfactory. The correlations between scores on the PDS and on the other depression scales were moderate to high. Mean PDS scores of patients with a diagnosis of depressive disorder were significantly higher than those of patients with other mental disorders.

Despite some limitations, this study suggests that the PDS a valid and reliable instrument which might prove particularly useful for the assessment of depressive symptoms in studies where issues of acceptability are important, such as studies on non-clinical populations, occupational samples, and patients drawn from non-psychiatric settings.