Dysphoria is associated with reduced cardiac vagal withdrawal during the imagery of pleasant scripts: evidence for the positive attenuation hypothesis.

The present study investigated emotional responding in dysphoric individuals. Dysphoric (N = 25) and nondysphoric (N = 29) individuals completed an emotional imagery task, including pleasant, neutral and unpleasant emotional-eliciting scripts. Self-reported valence and arousal, and measures of cardiac autonomic activity were collected during the task. Compared to nondysphoric controls, dysphoric individuals showed a reduced heart rate increase to pleasant scripts. Less vagal withdrawal in response to pleasant scripts was also found in dysphoric, but not in nondysphoric, individuals. Conversely, no differences between groups in autonomic responding to unpleasant scripts and in subjective measures were noted. Overall, our data showed that dysphoria is characterized by blunted cardiac autonomic reactivity in response to positive rather than negative emotional stimuli. The present findings also suggest that the lack of vagal suppression may reflect a reduced sensitivity to positive environmental stimuli, which, in turn, has been implicated in the development of major depression in dysphoric individuals.