J J Prisciandaro1, B K Tolliver1. 1. Department of Psychiatry and Behavioral Sciences,Medical University of South Carolina,Charleston,SC,USA.
Abstract
BACKGROUND: Evidence supporting the continuous latent structure of mood phenomena has not been incorporated into psychiatric diagnostic systems, in part because the evidence has been incomplete. For example, no studies have investigated the boundary between 'sick' and 'well' periods in individuals with bipolar disorder, despite agreement that characterization of mood disorders as having a discrete episodic course is inaccurate. The present study examined the validity of mood episode symptom thresholds in out-patients with bipolar disorder using multiple methodologies: taxometrics and information-theoretic latent distribution modeling (ITLDM), to evaluate the continuity/discontinuity of mood symptoms; and structural equation mixture modeling (SEMM), to evaluate the continuity/discontinuity of associations between mood symptoms and general functioning. METHOD: A total of 3721 out-patients with bipolar disorder from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) were available for analysis. Data were collected at participants' baseline STEP-BD visit. Taxometric [maximum covariance/means above minus below a cut (MAXCOV/MAMBAC) with simulated comparison data], ITLDM and SEMM methods were applied twice, once to the Montgomery-Åsberg Depression Rating Scale and again to the Young Mania Rating Scale. RESULTS: Taxometric results unequivocally supported a continuous interpretation of the data. ITLDM results favored many valued 'discrete metrical' models, suggesting that mood symptoms have continuous, but potentially non-normally distributed, latent structures in out-patients with bipolar disorder. Finally, SEMM results demonstrated that latent associations between mood symptoms and general functioning were linear. CONCLUSIONS: Results from the present study argue against the validity of DSM mood episode thresholds and argue for a graded continuum of care of bipolar symptom management.
BACKGROUND: Evidence supporting the continuous latent structure of mood phenomena has not been incorporated into psychiatric diagnostic systems, in part because the evidence has been incomplete. For example, no studies have investigated the boundary between 'sick' and 'well' periods in individuals with bipolar disorder, despite agreement that characterization of mood disorders as having a discrete episodic course is inaccurate. The present study examined the validity of mood episode symptom thresholds in out-patients with bipolar disorder using multiple methodologies: taxometrics and information-theoretic latent distribution modeling (ITLDM), to evaluate the continuity/discontinuity of mood symptoms; and structural equation mixture modeling (SEMM), to evaluate the continuity/discontinuity of associations between mood symptoms and general functioning. METHOD: A total of 3721 out-patients with bipolar disorder from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) were available for analysis. Data were collected at participants' baseline STEP-BD visit. Taxometric [maximum covariance/means above minus below a cut (MAXCOV/MAMBAC) with simulated comparison data], ITLDM and SEMM methods were applied twice, once to the Montgomery-Åsberg Depression Rating Scale and again to the Young Mania Rating Scale. RESULTS: Taxometric results unequivocally supported a continuous interpretation of the data. ITLDM results favored many valued 'discrete metrical' models, suggesting that mood symptoms have continuous, but potentially non-normally distributed, latent structures in out-patients with bipolar disorder. Finally, SEMM results demonstrated that latent associations between mood symptoms and general functioning were linear. CONCLUSIONS: Results from the present study argue against the validity of DSM mood episode thresholds and argue for a graded continuum of care of bipolar symptom management.
Authors: Anthony O Ahmed; Bradley A Green; Charles B Clark; Karyn C Stahl; Megan E McFarland Journal: Bipolar Disord Date: 2011 Aug-Sep Impact factor: 6.744
Authors: June Gruber; Anna Van Meter; Kirsten E Gilbert; Eric A Youngstrom; Jennifer Kogos Youngstrom; Norah C Feeny; Robert L Findling Journal: Cognit Ther Res Date: 2016-09-03