Two instruments commonly used in primary care research to measure depressive severity are the Patient Health Questionnaire-9 (PHQ-9) and the Hopkins Symptom Checklist-20 (HSCL-20). However, there is little information regarding the relationship between clinical information derived from these scales. The present study investigates the psychometric properties of the PHQ-9 and HSCL-20, determines the degree of instrument concordance, and describes the factor structure of the HSCL-20.
A secondary data analysis from a randomized controlled trial was performed. A total of 405 primary care patients with major depressive disorder and/or dysthymia were administered the PHQ-9 and the HSCL-20 when recruited for the study.
Good internal consistency reliability estimates were obtained for both scales (PHQ-9 alpha=0.803; HSCL-20 alpha=0.837). All PHQ-9 inter-item and corrected item-total correlations showed that no item detracted from overall scale functioning. HSCL-20 items assessing overeating, poor appetite, and sexual interest were poorly correlated with other items and with the total scale score. A positive, moderate strength relationship was found between the instruments (r=0.54, p<0.0001). Exploratory factor analysis of the HSCL-20 yielded a six-factor structure, which accounted for almost 63% of the variance in total score. The largest contribution to common variance in the scale was provided by an "anxiety and self-reproach" factor.
PHQ-9 and HSCL-20 total scores were moderately correlated. Although the HSCL-20 is utilized as a measure of depression severity, it may lack sufficient specificity to be an accurate reflection of depression status per se.
"Telephone administration of the Patient Health Questionnaire (PHQ9) has been validated in stroke patients (Lee et al. 2007). This instrument has demonstrated reliability as a screening tool for Post Stroke Depression (Williams et al. 2005). "
"The PHQ-9 (Kroenke et al., 2001) is a widely used selfreport measure of depression that is brief, easy to administer and has well-established psychometric properties (Lee et al., 2007). For these reasons it has been recommended as an integral part of the management of depression in primary care, including tracking symptom change and defining successful treatment outcome to inform treatment decisions (Clark et al., 2009; Dejesus et al., 2007). "
[Show abstract][Hide abstract] ABSTRACT: Although the PHQ-9 is widely used in primary care, little is known about its performance in quantifying improvement. The original validation study of the PHQ-9 defined clinically significant change as a post-treatment score of ≤9 combined with improvement of 50%, but it is unclear how this relates to other theoretically informed methods of defining successful outcome. We compared a range of definitions of clinically significant change (original definition, asymptomatic criterion, reliable and clinically significant change criteria a, b and c) in a clinical trial of a community-level depression intervention.
Randomised Control Trial of collaborative care for depression. Levels of agreement were calculated between the standard definition, other definitions, and gold-standard diagnostic interview.
The standard definition showed good agreement (kappa>0.60) with the other definitions and had moderate, though acceptable, agreement with the diagnostic interview (kappa=0.58). The standard definition corresponded closely to reliable and clinically significant change criterion c, the recommended method of quantifying improvement when clinical and non-clinical distributions overlap.
The absence of follow-up data meant that an asymptomatic criterion rather than remission or recovery criteria were used.
The close agreement between the standard definition and reliable and clinically significant change criterion c provides some support for the standard definition of improvement. However, it may be preferable to use a reliable change index rather than 50% improvement. Remission status, based on the asymptomatic range and a lower PHQ-9 score, may provide a useful additional category of clinical change.
"It was omitted because interviewers are not able to provide adequate intervention by telephone. Research indicates that the deletion of this question has only a minor effect on scoring because thoughts of self-harm are fairly uncommon in the general population, and the ninth item is by far the least frequently endorsed item on the PHQ-9 (Huang et al., 2006a; Kroenke and Spitzer, 2002; Lee et al., 2007; Rief et al., 2004). Indeed, the two original validation studies of the PHQ totaling 6000 patients established that identical scoring thresholds for depression severity could be used for the PHQ-9 and PHQ-8 (Kroenke and Spitzer, 2002). "
[Show abstract][Hide abstract] ABSTRACT: The eight-item Patient Health Questionnaire depression scale (PHQ-8) is established as a valid diagnostic and severity measure for depressive disorders in large clinical studies. Our objectives were to assess the PHQ-8 as a depression measure in a large, epidemiological population-based study, and to determine the comparability of depression as defined by the PHQ-8 diagnostic algorithm vs. a PHQ-8 cutpoint > or = 10.
Random-digit-dialed telephone survey of 198,678 participants in the 2006 Behavioral Risk Factor Surveillance Survey (BRFSS), a population-based survey in the United States. Current depression as defined by either the DSM-IV based diagnostic algorithm (i.e., major depressive or other depressive disorder) of the PHQ-8 or a PHQ-8 score > or = 10; respondent sociodemographic characteristics; number of days of impairment in the past 30 days in multiple domains of health-related quality of life (HRQoL).
The prevalence of current depression was similar whether defined by the diagnostic algorithm or a PHQ-8 score > or = 10 (9.1% vs. 8.6%). Depressed patients had substantially more days of impairment across multiple domains of HRQoL, and the impairment was nearly identical in depressed groups defined by either method. Of the 17,040 respondents with a PHQ-8 score > or = 10, major depressive disorder was present in 49.7%, other depressive disorder in 23.9%, depressed mood or anhedonia in another 22.8%, and no evidence of depressive disorder or depressive symptoms in only 3.5%.
The PHQ-8 diagnostic algorithm rather than an independent structured psychiatric interview was used as the criterion standard.
The PHQ-8 is a useful depression measure for population-based studies, and either its diagnostic algorithm or a cutpoint > or = 10 can be used for defining current depression.
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