Distinguishing bipolar major depression from unipolar major depression with the screening assessment of depression-polarity (SAD-P).

Full Abstract

BACKGROUND:
Patients with bipolar I or II major depression are often misdiagnosed with unipolar major depression. The goal of this study was to develop and validate a brief instrument to screen for bipolar disorder in patients actively ill with major depression.

METHOD:
The sample consisted of subjects who enrolled in the National Institute of Mental Health-Collaborative Program on the Psychobiology of Depression-Clinical Studies from 1978 to 1981 during an episode of major depression and included 91 subjects with bipolar I major depression, 52 with bipolar II major depression, and 338 with unipolar major depression diagnosed according to Research Diagnostic Criteria. Most of the subjects were inpatients at the time of enrollment, and subjects were prospectively followed for up to 20 years. In order to create, test, and cross-validate the screening instrument, a split-sample data analytic procedure was performed. This procedure yielded 3 groups of subjects:
the bipolar I index sample, the bipolar I cross-validation sample, and the bipolar II cross-validation sample. Each group included subjects with bipolar major depression and subjects with unipolar major depression. Within the bipolar I index sample, subjects with bipolar I major depression at study intake were compared with subjects with unipolar major depression at study intake on a pool of 59 sociodemographic and clinical candidate variables. The 3 variables showing the greatest disparity between bipolar I subjects and unipolar subjects were selected for the screen, the Screening Assessment of Depression-Polarity (SAD-P). The operating characteristics of the SAD-P were then examined within the bipolar I index sample, bipolar I cross-validation sample, and bipolar II cross-validation sample.

RESULTS:
The items selected for the screening instrument were (1) presence of delusions during the current episode of major depression, (2) number of prior episodes of major depression, and (3) family history of major depression or mania. The screen identified bipolar major depression with a sensitivity of 0.82 in the bipolar I index sample, 0.72 in the bipolar I cross-validation sample, and 0.58 in the bipolar II cross-validation sample. With regard to misclassifying subjects with unipolar major depression, the screen provided a positive predictive value of 0.36 in the bipolar I index sample, 0.29 in the bipolar I cross-validation sample, and 0.27 in the bipolar II cross-validation sample.

CONCLUSION:
We suggest using the 3-item SAD-P as a preliminary screen for bipolar disorder in patients who present with an active episode of major depression.

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Author information

Author/s: Solomon, David A (DA); Leon, Andrew C (AC); Maser, Jack D (JD); Truman, Christine J (CJ); Coryell, William (W); Endicott, Jean (J); Teres, Jedediah J (JJ); Keller, Martin B (MB);

Affiliation: Department of Psychiatry and Human Behavior, Brown University, Providence, RI, USA. DASolomon(-atsign-)Lifespan.org

Grants: 2R10MH25478-29A2 (Agency:NIMH NIH HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Multicenter Study; Research Support, N.I.H., Extramural

Journal: The Journal of clinical psychiatry (J Clin Psychiatry), published in United States. (Language: eng)

Reference: 2006-Mar; vol 67 (issue 3) : pp 434-42

Dates: Created 2006/05/02; Completed 2006/05/17; Revised 2007/11/14;

PMID: 16649831, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Bipolar Disorder - diagnosis; psychology
Delusions - diagnosis
Depressive Disorder - diagnosis; psychology
Depressive Disorder, Major - diagnosis; psychology
Diagnosis, Differential
Family
Female
Hospitalization
Humans

Humans
Longitudinal Studies
Male
Mass Screening - methods
Prospective Studies
Psychiatric Status Rating Scales - statistics & numerical data
Psychometrics
ROC Curve
Reproducibility of Results
Sensitivity and Specificity

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