Deficits in attention to emotional stimuli distinguish youth with severe mood dysregulation from youth with bipolar disorder

Abstract

Studying attention in the context of emotional stimuli may aid in differentiating pediatric bipolar disorder (BD) from severe mood dysregulation (SMD). SMD is characterized by chronic irritability, arousal, and hyper-reactivity; SMD youth frequently receive a BD diagnosis although they do not meet DSM-IV criteria for BD because they lack manic episodes. We compared 57 BD (14.4 +/- 2.9 years old, 56% male), 41 SMD (12.6 +/- 2.6 years old, 66% male), and 33 control subjects (13.7 +/- 2.5 years old, 52% male) using the Emotional Interrupt task, which examines how attention is impacted by positive, negative, or neutral distracters. We compared reaction time (RT) and accuracy and calculated attention interference scores by subtracting performance on neutral trials from emotional trials. Between-group analyses indicated that SMD subjects had significantly reduced attention interference from emotional distracters relative to BD and control subjects. Thus, attention in SMD youth was not modulated by emotional stimuli. This blunted response in SMD youth may contribute to their affective and behavioral dysregulation.

Fig. 1

The Emotional Interrupt Task. Figure depicts the stimuli (distracter pictures: neutral, positive, or negative; targets: circle or square) and their presentation timecourse. Subject must press a button that corresponds to the circle/square target while ignoring the distracter pictures

Fig. 2

Group Differences in Reaction Time. Figure depicts group differences in reaction time (RT) on trials involving neutral, negative, and positive distracting pictures. Within-group found significant effects of picture emotion in both controls [F(2,64)=20.24, p<0.001] and BD subjects [F(2,112)=12.06, p<0.001]; both samples were significantly slower on the negative a and positive b picture trials when compared to neutral trials (p<0.001). However, the effect of emotion was nonsignificant in SMD subjects [F(2,80)=2.05, p=0.16], suggesting that their performance did not vary as a function of the emotional nature of the distracting picture. CON control subjects; BD bipolar disorder; SMD severe mood dysregulation

Fig. 3

Group Differences in Reaction Time Attention Interference Scores. Figure depicts group differences in the reaction time (RT) attention interference score. Attention interference score = RT on trials with an emotional distracter—RT on trials with a neutral distracter. Scores are adjusted after controlling for age and IQ. On negative pictures, SMD subjects displayed a significantly lower attention interference compared to controls (p<0.0001) and BD subjects (p< 0.0001). Similarly, on positive pictures, SMD subjects displayed a significantly lower attention interference compared to controls (p< 0.001) and BD subjects (p<0.0001). Results indicate a blunted response to emotional stimuli in SMD subjects. BD bipolar disorder; SMD severe mood dysregulation; CON control subjects