Negative emotion impairs working memory in pediatric patients with bipolar disorder type I.

Abstract

We investigated affect recognition and the impact of emotional valence on working memory (using happy, angry, and neutral faces) in pediatric patients with bipolar disorder (BD) and healthy control (HC) subjects. Subjects (N=70) consisted of unmedicated patients with BD type I (BD I, n=23) and type II (BD II, n=16) and matched HC subjects (n=31). All subjects completed tasks of emotion recognition (Chicago Pediatric Emotional Acuity Task; Chicago PEAT) and working memory for happy, angry, and neutral faces (Affective N-Back Memory Task; ANMT). Compared to HC subjects, BD patients performed significantly more poorly when identifying the intensity of happy and angry expressions on the Chicago PEAT, and demonstrated working-memory impairments regardless of the type of facial emotional stimuli. Pediatric BD patients displayed the most impaired accuracy and reaction time performance with negative facial stimuli relative to neutral stimuli, but did not display this pattern with positive stimuli. Only BD I patients displayed working-memory deficits, while both BD I and BD II patients displayed emotion-identification impairments. Results remained significant after controlling for co-morbid ADHD and mood state. Both BD I and BD II youth demonstrate emotion-identification deficits. BD youth also demonstrate working-memory impairments for facial stimuli irrespective of emotional valence; however, working-memory deficits were the most pronounced with negative emotional stimuli. These deficits appear to be specific to BD I patients, and suggest therefore that a more severe form of illness is characterized by more severe social-cognitive impairment.