A cross-validation of the provisional diagnostic instrument (PDI-4).

Abstract

BACKGROUND:

The Provisional Diagnostic Instrument (PDI-4) is a brief, adult self-report instrument for 4 common psychiatric diagnoses in primary care patients: major depressive episode (MDE), generalized anxiety disorder (GAD), attention deficit hyperactivity disorder (ADHD), and bipolar I disorder based on past or present mania. Our objective was to assess validity of the PDI-4 in a population independent of the study population originally used to develop the scale.

METHODS:

An online version of the 17-item PDI-4 was administered to 1,047 adults in the US; respondents also completed the PHQ-9, HADS-A, CAARS-S, and MDQ within the online survey. Respondents self-reported diagnosis by a healthcare professional with the terms depression (n=221), anxiety (n=218), attention deficit disorder (n=206), bipolar or manic depressive disorder (n=195), or none of these (n=207). Statistical analyses examined convergent and discriminant validity, and operating characteristics of the PDI-4 relative to the individual, validated, self-rated scales PHQ-9, HADS-A, CAARS-S, and MDQ, for each PDI-4 diagnosis.

RESULTS:

Convergent validity of the PDI-4 was supported by strong correlations with the corresponding individual scales (range of 0.63 [PDI-4 and MDQ] to 0.87 [PDI-4 and PHQ-9]). Operating characteristics of the PDI-4 were similar to results in the previous site-based study. The scale exhibited moderate sensitivities (0.52 [mania] to 0.70 [ADHD]) and strong specificities (0.86 [mania] to 0.92 [GAD]) using the individual scales as the gold standards. ANOVAs demonstrated that PDI-4 discriminated between subsets of patients defined by pre-specified severity level cutoff scores of the individual scales. However, overlapping symptoms and co-morbidities made differentiation between mental diagnoses much weaker than differentiation from the control group with none of the diagnoses.

CONCLUSIONS:

The PDI-4 appears to be a suitable, brief, self-rated tool for provisional diagnoses of common mental disorders. However, the high level of symptom overlap between these diagnoses emphasizes that such brief scales are not a replacement for thorough diagnostic evaluation by trained medical providers.

• Authors: Douglas E Faries, John P Houston, Ellen M Sulcs, Ralph W Swindle
• Journal: BMC family practice (BMC Fam Pract) Vol. 13 Pg. 104 (Oct 15 2012) ISSN: 1471-2296 [Electronic] England
• PMID: 23067304 (Publication Type: Journal Article, Validation Study)

Topics

• Adult
• Aged
• Anxiety Disorders (diagnosis)
• Attention Deficit Disorder with Hyperactivity (diagnosis)
• Bipolar Disorder (diagnosis)
• Cohort Studies
• Cross-Sectional Studies
• Depressive Disorder, Major (diagnosis)
• Female
• Humans
• Male
• Middle Aged
• Psychometrics
• Reproducibility of Results
• Self Report
• Sensitivity and Specificity
• Surveys and Questionnaires