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Open Access Research article

Psychometric properties of the self-report version of the Quick Inventory of Depressive Symptoms (QIDS-SR16) questionnaire in patients with schizophrenia

Irene M Lako1, Johanna TW Wigman23, Rianne MC Klaassen4, Cees J Slooff5, Katja Taxis1 and Agna A Bartels-Velthuis2*

Author Affiliations

1 Division of Pharmacotherapy and Pharmaceutical Care, Department of Pharmacy, University of Groningen, Groningen, The Netherlands

2 University of Groningen, University Medical Center Groningen, University Center for Psychiatry, Rob Giel Research Center, Groningen, The Netherlands

3 Department of Psychiatry and Psychology, Maastricht University Medical Center, Maastricht, The Netherlands

4 Rivierduinen Mental Health, Leiden, The Netherlands

5 Department of Psychotic Disorders, Mental Health Center Assen (GGZ Drenthe), Assen, Netherlands

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BMC Psychiatry 2014, 14:247  doi:10.1186/s12888-014-0247-2

Published: 3 September 2014

Abstract

Background

Self-report instruments for the assessment of depressive symptoms in patients with psychotic disorders are scarce. The Quick Inventory of Depressive Symptoms (QIDS-SR16) may be a useful self-report instrument, but has received little attention in this field. This paper aimed to test the psychometric properties of the QIDS-SR16 questionnaire in patients with a psychotic disorder.

Methods

Patients diagnosed with a psychotic disorder from health care institutions in The Netherlands were included in the study. Depressive symptoms were assessed with the QIDS-SR16 and the Calgary Depression Scale for Schizophrenia (CDSS). Psychotic symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) and extrapyramidal symptoms (EPS) with three EPS rating scales. Spearman’s correlation coefficients were used to compare the total score of the QIDS-SR16 with the total scores of the CDSS, PANSS-subscales and EPS rating scales.

Results

In a sample of 621 patients with psychotic disorders, the QIDS-SR16 showed good internal consistency (α = 0.87). The QIDS-SR16 correlated moderately with the CDSS (r = 0.44) and the PANSS subscale for emotional distress (r = 0.47). The QIDS-SR16 showed weak correlation with the PANSS subscale for negative symptoms (r = 0.28) and minimal correlation with EPS rating scales (r = 0.09-0.16).

Conclusions

The QIDS-SR16 may reliably assess depressive symptoms in patients with psychotic disorders, but its concurrent validity with the CDSS was rather poor in this population. We would recommend developing a new self-report questionnaire for the assessment of depressive symptoms in patients with psychotic disorders.