title: The factor structure of clinical symptoms in depressed inpatients with unipolar or bipolar spectrum disorders: a preliminary study.
abstract: Factor analysis of symptom structure has proven to be a valuable tool to identify dimensions of symptoms in various psychiatric conditions. This study used exploratory and confirmatory factor analysis to examine symptom structures in depressed inpatients with unipolar (n = 718) or bipolar (n = 134) spectrum disorders who were rated at admission with a psychiatric rating scale. No differences in overall symptom severity on the scale were found in the 2 samples, although different factor structures were detected with exploratory analyses. These models were modified in a confirmatory modeling procedure to improve their fit to the data, resulting in models with good, but not perfect, fits. For people with bipolar disorders, a 5-factor model fit best, with depression loading with anxiety symptoms and in people with unipolar disorders, a 4-factor model with depression loading with vegetative symptoms was found. Our results suggest that similar levels of symptom severity may have different underpinnings in the 2 groups and suggest that more comparative studies of symptoms in these 2 conditions may be useful.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia 30322, USA. philipdharvey1@cs.com
authors.forename: Philip D
authors.initials: PD
authors.lastname: Harvey
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Young
authors.forename: Abraham
authors.initials: A
authors.lastname: Reichenberg
authors.forename: David L
authors.initials: DL
authors.lastname: Pogge
mesh_terms: D000293:Adolescent; D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000523:psychology; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology; D005163:Factor Analysis, Statistical; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult