What Is Hypomania? Tetrachoric Factor Analysis and Kernel Estimation of <i>DSM-IV</i> Hypomanic Symptoms
J Clin Psychiatry 2009;70(11):1514-1521
© Copyright 2016 Physicians Postgraduate Press, Inc.
Purchase This PDF for $40.00
If you are not a paid subscriber, you may purchase the PDF.
(You'll need the free Adobe Acrobat Reader.)
Receive immediate full-text access to JCP. You can subscribe to JCP online-only ($86) or print + online ($156 individual).
With your subscription, receive a free PDF collection of the NCDEU Festschrift articles. Hurry! This offer ends December 31, 2011.
If you are a paid subscriber to JCP and do not yet have a username and password, activate your subscription now.
As a paid subscriber who has activated your subscription, you have access to the HTML and PDF versions of this item.
Click here to login.
Did you forget your password?
Still can't log in? Contact the Circulation Department at 1-800-489-1001 x4 or send email
Background: The DSM-IV definition of hypomania, which relies on clinical consensus and historical tradition, includes several “nonspecific” symptoms. The
aim of this study was to identify the core symptoms
of DSM-IV hypomania.
Method: In an outpatient private practice, 266 bipolar II disorder (BP-II) and 138 major depressive disorder (MDD) remitted patients were interviewed by a bipolar-trained psychiatrist, for different study goals. Patients were questioned, using the Structured Clinical Interview for DSM-IV, about the most common symptoms and duration of recent threshold and subthreshold hypomanic episodes. Data were recorded between 2002
and 2006. Four different samples, assessed with the
same methodology, were pooled for the present analyses.
Tetrachoric factor analysis was used to identify core
hypomanic symptoms. Distribution of symptoms by kernel estimation was inspected for bimodality. Validity of core hypomania was tested by receiver operating characteristic (ROC) analysis.
Results: The distribution of subthreshold and threshold hypomanic episodes did not show bimodality. Tetrachoric factor analysis found 2 uncorrelated factors: factor 1 included the “classic” symptoms elevated mood, inflated self-esteem, decreased need for sleep, talkativeness, and increase in goal-directed activity (overactivity); factor 2 included the “nonspecific” symptoms irritable mood, racing/crowded thoughts, and distractibility.
Factor 1 discriminatory accuracy for distinguishing
BP-II versus MDD was high (ROC area = 0.94). The
distribution of the 5-symptom episodes of factor 1 showed clear-cut bimodality. Similar results were found for episodes limited to 3 behavioral symptoms of factor 1 (decreased need for sleep, talkativeness, and overactivity) and 4 behavioral symptoms of factor 1 (adding elevated mood), with high discriminatory accuracy.
Conclusions: A core, categorical DSM-IV hypomania was found that included 3 to 5 symptoms, ie, behavioral symptoms and elevated mood. Behavioral symptoms (overactivity domain) could be the basic phenotype of hypomania. This finding could help in probing for hypomania and reduce misdiagnosis. Biologic research could focus more on the underpinnings of the overactivity domain specifically.
Submitted: February 1, 2009; accepted March 17, 2009.
Online ahead of print: September 8, 2009.
Corresponding author: Franco Benazzi, MD, Via Pozzetto 17, 48015 Castiglione Cervia RA, Italy (FrancoBenazzi@FBenazzi.it).