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Psychometric validation of the Perceived Deficits Questionnaire-Depression (PDQ-D) instrument in US and UK respondents with major depressive disorder

Authors Lam RW, Lamy FX, Danchenko N, Yarlas A, White MK, Rive B, Saragoussi D

Received 24 May 2018

Accepted for publication 20 July 2018

Published 29 October 2018 Volume 2018:14 Pages 2861—2877


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Roger Pinder

Raymond W Lam,1 François-Xavier Lamy,2 Natalya Danchenko,2 Aaron Yarlas,3 Michelle K White,3 Benoît Rive,2 Delphine Saragoussi2

1Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada; 2Global Outcomes Research, Lundbeck SAS, Issy-les-Moulineaux, France; 3Optum Patient Insights, Optum, Inc., Lincoln, RI, USA

Although depression and cognitive dysfunction are connected, limited tools exist to capture the patient’s perspective on cognitive dysfunction and its impact on major depressive disorder (MDD). We report results of a psychometric validation of the Perceived Deficits Questionnaire-Depression (PDQ-D), a self-report measure of cognitive dysfunction for use in MDD.
Methods: A non-interventional, prospective, panel-recruited, online survey was conducted using the PDQ-D in adults with and without MDD in the US and UK. Respondents were assessed at baseline and after 6 weeks (MDD only) (baseline: US n=418, UK n=437, 49% MDD; follow-up: US n=169, UK n=153, all MDD). The criterion measures included: Medical Outcomes Study Cognitive Functioning Scale-Revised-acute form (MOS COG-R), Patient Health Questionnaire-9 (PHQ-9), Patient Global Impression of Severity scale (PGI-Severity), Sheehan Disability Scale (SDS), Work Productivity and Activity Impairment Questionnaire: Specific-Health Problem (WPAI:SHP), and modified Lam Employment Absence and Productivity Scale (LEAPS). US and UK data were analyzed separately.
Results: Internal consistency was high for PDQ-D total scale and four subscales (Cronbach’s alpha 0.81–0.96). Convergent validity was good, with strong concordance with MOS COG-R and moderate/small correlations with PHQ-9, SDS, WPAI:SHP, LEAPS, and PGI-Severity. Significant differences (all P<0.001) existed for all PDQ-D subscale and total scores between MDD/non-MDD samples. The PDQ-D was responsive to changes in depression symptom severity. Confirmatory factor analysis supported scoring of a global overall scale for perceived cognitive dysfunction.
Conclusion: The PDQ-D provides a reliable and valid measure of subjective cognitive dysfunction in patients with MDD.

Keywords: major depressive disorder, cognitive dysfunction, psychometric validation, self-report

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