Ruminative and dampening responses to positive affect in bipolar disorder and major depressive disorder

Background: Although previous research has focused on distinguishing cognitive styles between Bipolar Disorder (BD) and Major Depressive Disorder (MDD), little is known about differences in positive affect regulation between these affective groups. The aim of the present study was to extend previous research by investigating such differences between BD and MDD, and between the bipolar subtypes (BD-I vs. BD-II and predominant polarities), using large, clinical, outpatient samples. Methods: In total, 298 participants (96 BD-I, 27 BD-II, and 175 MDD) were included. All completed the Responses to Positive Affect (RPA) questionnaire. Mood symptoms in BD patients were clinically assessed by means of the Clinical Global Impression for Bipolar Disorders (CGI-BP), while depressive symptom severity in MDD patients were assessed by means of the Inventory of Depressive Symptomatology (IDS-SR). Results: Results showed differences between affective groups and bipolar subtypes. The most salient finding was that both BD-I and BD-II patients were more likely to ruminate about positive affect than MDD patients, while MDD patients were more likely to engage in dampening responses to positive affect. Conclusions: Differentiation of responses to positive affect between BD and MDD may have relevant clinical implications in terms of symptomatology, course, and treatment. (C) 2018 Elsevier Inc. All rights reserved.