Diagnostic Accuracy of the Primary Care Screener for Affective Disorder (PC-SAD) in Primary Care.

BACKGROUND: Depression goes often unrecognised and untreated in non-psychiatric medical settings. Screening has recently gained acceptance as a first step towards improving depression recognition and management. The Primary Care Screener for Affective Disorders (PC-SAD) is a self-administered questionnaire to screen for Major Depressive Disorder (MDD) and Dysthymic Disorder (Dys) which has a sophisticated scoring algorithm that confers several advantages. This study tested its performance against a 'gold standard' diagnostic interview in primary care. METHODS: A total of 416 adults attending 13 urban general internal medicine primary care practices completed the PC-SAD. Of 409 who returned a valid PC-SAD, all those scoring positive (N=151) and a random sample (N=106) of those scoring negative were selected for a 3-month telephone follow-up assessment including the administration of the Structured Clinical Interview for DSM-IV-TR Axis I Disorders (SCID-I) by a psychiatrist who was masked to PC-SAD results. RESULTS: Most selected patients (N=212) took part in the follow-up assessment. After adjustment for partial verification bias the sensitivity, specificity, positive and negative predictive value for MDD were 90%, 83%, 51%, and 98%. For Dys, the corresponding figures were 78%, 79%, 8%, and 88%. CONCLUSIONS: While some study limitations suggest caution in interpreting our results, this study corroborated the diagnostic validity of the PC-SAD, although the low PPV may limit its usefulness with regard to Dys. Given its good psychometric properties and the short average administration time, the PC-SAD might be the screening instrument of choice in settings where the technology for computer automated scoring is available.

Development and preliminary validation of the PC-SAD5, a screener-derived short depression severity measure.

BACKGROUND: The prevalence of depressive disorders is high among patients with skin disease. The PC-SAD is a 37-item self-administered depression screening questionnaire that has been validated in dermatological patients. OBJECTIVE: The aim of this study was to develop and validate a brief depression severity instrument derived from the PC-SAD that can be used to assess severity and monitor ongoing clinical course. METHODS: Two patient samples participated in the study: 72 adult dermatological inpatients and 73 adults attending six primary care practices. Psychiatric assessment included the Structured Clinical Interview for DSM-IV and an 18-item version of the PC-SAD; moreover, dermatological patients completed the Patient Health Questionnaire depression scale (PHQ-9), while primary care patients were administered the Montgomery-Asberg Depression Rating Scale (MADRS). A subset of five PC-SAD items showing the best psychometric properties were selected, and the reliability and validity of the resulting instrument (PC-SAD5) were examined. RESULTS: The PC-SAD5 showed satisfactory internal consistency in both samples. There was a high correlation between PC-SAD5 and PHQ-9 and MADRS scores. Multiple regression analysis revealed a gradient of PC-SAD5 scores from patients with no mental disorder, those with milder forms of depression, to those with Major Depressive Disorder. Similar results were observed for the 18-item version of the PC-SAD. CONCLUSION: The availability of valid and reliable continuous measures of depression severity derived from the PC-SAD extends its field of application from depression screening to use as a follow-up measure of depression severity in routine clinical practice. A validated very short instrument such as the PC-SAD5 may have substantial clinical value.

A randomised controlled trial of the effectiveness of a program for early detection and treatment of depression in primary care.

OBJECTIVE: There is considerable uncertainty about whether depression screening programs in primary care may improve outcomes and what specific features of such programs may contribute to success. We tested the effectiveness of a program involving substantial commitment from local mental health services. METHODS: Prospective, randomised, patient- and evaluator-masked, parallel-group, controlled study. Participants were recruited in several urban primary care practices where they completed the PC-SAD screener and WHOQOL-Bref. Those who screened positive and did not report suicidal ideation (N=115) were randomised to an intervention group (communication of the result and offer of psychiatric evaluation and treatment free of charge; N=56) or a control group (no feedback on test result for 3 months; N=59). After 3 months, 100 patients agreed to a follow-up telephone interview including the administration of the PC-SAD5 and WHOQOL-Bref. RESULTS: Depression severity and quality of life improved significantly in both groups. Intent-to-treat analysis showed no effect of the intervention. As only 37% of patients randomised to the intervention group actually contacted the study outpatient clinic, we performed a per-protocol analysis to determine whether the intervention, if delivered as planned, had been effective. This analysis revealed a significant positive effect of the intervention on severity of depressive symptoms, and on response and remission rate. Complier average causal effect analysis yielded similar results. CONCLUSION: Due to the relatively small sample size, our findings should be regarded as preliminary and have limited generalizability. They suggest that there are considerable barriers on the part of many patients to the implementation of depression screening programs in primary care. While such programs can be effective, they should be designed based on the understanding of patients' perspectives.