Replication and extension: separate personality traits from states to predict depression

Abstract

Changes in personality trait levels often parallel episodes of major depressive disorder (MDD), whereas trait factor structures and substantial retest correlations are preserved. The authors explicated this dual state/trait nature of personality assessments among adults with recurrent MDD (N = 351) receiving cognitive therapy (CT) by testing stability and change with the Schedule for Nonadaptive and Adaptive Personality, 2nd Edition (SNAP-2; Clark, Simms, Wu, & Casillas, in press), separating state and trait variance, and predicting depressive symptoms and clinical outcomes. Many SNAP scale scores changed in CT (e.g., positive temperament increased, negative temperament decreased), and decreases in depressive symptoms accounted for most scales' score changes. Nonetheless, SNAP scales' state and trait components predicted depressive symptoms early and late in CT as well as clinical outcomes, and state components predicted changes in symptoms and clinical outcomes. These results support the validity of the SNAP-2 among depressed patients and highlight the salience of personalityrelevant state affect.

Conflict of interest statement

Dr. Vittengl has no financial interest or conflict of interest in the research.

Dr. Thase reports no conflicts of interest pertaining to this work. However, during the past three years, he has received income from or has other interests in relation to the following organizations. Honoraria and advisory boards: Aldolor, Alkermes, AstraZeneca, Bristol-Myers Squibb, Eli Lilly & Co., Forest Laboratories, Gerson Lehman Group, GlaxoSmithKline, Guidepoint Global, H. Lundbeck A/S, MedAvante, Inc., Merck (Organon; Schering-Plough), Neuronetics Inc., Novartis, Otsuka, Ortho-McNeil (Johnson & Johnson), PamLab, Pfizer (Wyeth), PharmaNeuroboost, Rexahn, Roche Inc, Shire US Inc., Supernus, Takeda, Transcept. Research grants: Agency for Healthcare Research and Quality, Eli Lilly & Co., Forest Pharmaceuticals, GlaxoSmithKline, NIMH, Otsuka Pharmaceuticals, Pfizer Pharmaceuticals.