Quality of Life in Depression Scale
According to Kennedy, Eisfeld, and Cooke (2001, p. 23), the concept of quality of life serves to evaluate the efficacy of treatment intervention from the patient’s perspective and how they influence a person’s overall sense of well-being and satisfaction with life. The theoretical foundation of the Quality of Life in Depression Scale (QLDS) is that quality of life derives from the patient’s own aptitude and capacity to fulfill their individual needs (Kennedy et al. 2001, p. 25).
Psychometric Properties of QLDS
To create the QLDS, researchers conducted interviews with patients who had active or recent depression treated by psychotropic medication to discover how their depression affected their quality of life (Tuynman-Qua, Jonghe, and McKenna, 1997, p. 8). The interviewers extrapolated 75 general statements from the interviews and eventually winnowed the total number to 35 positive and negative statements about their quality of life (Tuynman-Qua, Jonghe, and McKenna, 1997, p. 8). The respondents who complete the QLDS respond either “true” or “not true” to these statements which include examples such as, “I feel as if I am not in control of my life” and “I look forward to things” (Tuynman-Qua, Jonghe, and McKenna, 1997, p. 8).
Appropriate Utilization of QLDS
De Fruyt and Demyttenaere (2009, p. 214), discuss that health is not merely defined or measured as the absence of disease but a more holistic state of total well-being in the realms of physical, mental, and social health. This comprehensive understanding of health requires more than objective metrics like diagnostic imaging and blood tests to determine the absence of disease. Instead, implementation of a questionnaire such as the QLDS serves to gather essential data on the patient’s perception of their current state of well-being (Tuynman-Qua, Jonghe, and McKenna, 1997, p. 12). Tuynman-Qua, Jonghe, and McKenna (1997, p. 4), note that the presence of objectively identifiable symptoms and disease correlates less with health care utilization than the patient’s perception of feeling unwell. Additionally, patient perception of effect on well-being also correlates treatment compliance (Tuynman-Qua, Jonghe, and McKenna, 1997, p. 12). Therefore, it is appropriate to implement the QLDS before and after the implementation of a psychopharmacological intervention to understand the patient’s perception of benefit from treatment on their overall well-being
The QLDS is appropriate for use to evaluate the efficacy of psychopharmacologic medications. Per Fruyt and Demyttenaere (2009, p. 216), a Medline search for the utilization of the QLDS in Antidepressant trials found eight papers that used the QLDS. In one study on the efficacy of treatment of Major Depression (MD) with duloxetine in 40 to 55-year-old women, the study utilized the QLDS to capture the patient-perceived quality of life pre and post-treatment (Burt, Wohlreich, Mallinckrodt, Detke, Watkin, and Stewart, 2005, p. 345). The QLDS captured improved perception of quality of life consistent with improvements seen in both clinician-rated scales such as Hamilton Depression Scale and Clinician Global Impression as well as the patient-rated Patient Global Impression of Improvement Scale (Burt et al. 2005, p. 351).
