A study on the measurement of depressive symptoms: frequency versus intensity

Depression is a common mental health disorder and is a major contributor to the overall global burden of disease. Improving the instruments that are used to detect and assist in the diagnosis of depression is of importance due to the impact that the disorder has on the individual and society. The study aimed to explore and improve the measurement of depression. Seventy-one participants’ results on the PHQ-9 (that measures frequency of depressive symptoms) and the Borg CR scale® (measuring intensity of depressive symptoms) were analysed. It was also of interest to measure mental health patients’ (n = 16) self-rated depression and compare it to mental health staffs’ (n = 7) observer-rated depression. The overall correlation between intensity and frequency of depressive symptoms was found to be positively strong (r =. 695), the Borg CR scale showed high internal consistency when used for measuring intensity of depressive symptoms (.846), self-reported depression was lower than observer-rated depression (p = .167). In addition, inter-individual differences in frequency and intensity of depressive symptoms were also examined. Overall, the outcome of this study showed that intensity of depressive symptoms can differ considerably between individuals, despite similar overall depression scores.