Reduced positive emotion and underarousal are uniquely associated with subclinical depression symptoms: Evidence from psychophysiology, self-report, and symptom clusters

Abstract

Multiple models of aberrant emotional processing in depression have been advanced. However, it is unclear which of these models best applies to emotional disturbances in subclinical depressive symptoms. The current study employed a battery of psychophysiological measures and emotional ratings in a picture-viewing paradigm to examine whether the underarousal, low positive emotion, heightened negative emotion, or emotion context insensitivity model of emotional dysfunction in subclinical depressive symptoms received greatest support. Postauricular reflex and skin conductance response potentiation for pleasant minus neutral pictures (measuring low positive emotion), overall skin conductance magnitude and late positive potential (LPP) amplitude (measuring underarousal), and pleasant minus aversive valence ratings (measuring emotion context insensitivity) and aversive minus neutral arousal ratings (measuring heightened negative emotionality) were all negatively related to depressive symptomatology. Of these, postauricular reflex potentiation and overall LPP amplitude were incrementally associated with depressive symptoms over the other measures. Postauricular reflex potentiation, overall skin conductance magnitude, and aversive minus neutral arousal ratings were incrementally associated with depressive symptomatology after controlling for other symptoms of internalizing disorders. Though no model was unequivocally superior, the low positive emotion and underarousal models received the most support from physiological measures and symptom reports, with self-report data matching patterns consistent with the emotion context insensitivity model.

Keywords: depression; emotion context insensitivity; low positive emotion; postauricular reflex; skin conductance; underarousal.

Figure 1

Schematic representation of patterns of results predicted from various models of emotional dysfunction in depression. Each panel represents the pattern of correlations between depressive symptomatology and various emotional contrasts that would support the model depicted. Panel A represents the underarousal model of depression, panel B the low positive emotion (PEM) model, panel C the high negative emotion (NEM) model, and panel D the emotion context insensitivity (ECI) model. Mean = overall mean magnitude (green), +/0 = pleasant minus neutral (blue), −/0 = aversive minus neutral (red), +/− = pleasant minus aversive (purple). To clarify these expected results, each inset diagram depicts the patterns of emotional modulation predicted for depressed (Hi) versus nondepressed (Lo) participants in each model of emotional dysfunction with arbitrary y axis units. + = pleasant, 0 = neutral, − = aversive.

Figure 2

Main effects of valence on all measures in this study. Error bars represent the standard error of the mean. + = pleasant, 0 = neutral, − = aversive.

Figure 3

Correlations of total depressive symptomatology with the mean and emotional modulation of each measure. The patterns of correlations in each panel may be compared with those depicted in Figure 1 to ascertain which models of emotional dysfunction in depression are supported for a given measure. Correlations outside the dashed lines are significant at an α level of .05. Mean = overall mean magnitude (green), +/0 = pleasant minus neutral (blue), −/0 = aversive minus neutral (red), +/− = pleasant minus aversive (purple). n = 65 for skin conductance response, n = 79 for LPP amplitude, n = 83 for postauricular and startle blink reflexes, n = 87 for zygomatic and corrugator EMGs and for pleasantness and arousal ratings. Given the α level of .05, there were more significant correlations than would be expected by chance alone, binomial test p = .005. To clarify these results, each inset diagram displays the patterns of emotional reactivity for participants 1 SD above the mean in depressive symptoms (Hi) compared to all other participants (Lo). Error bars represent the error term of the Valence × Group interaction.