Mental state decoding in past major depression: Effect of sad versus happy mood induction

Abstract

Individuals with mild depression show an enhanced ability to read or “decode” others' mental states. The goal of the present study was to investigate whether this pattern of performance is related specifically to the pathology of depression or whether it is simply a feature of the transient dysphoric state. Forty-one undergraduates with a previous episode of major depression and 52 undergraduates with no depression history participated in a mental state decoding task following a sad versus happy mood induction. Previously depressed participants were significantly more accurate in their mental state judgements than were the never-depressed participants, suggesting that enhanced mental state decoding may be a specific feature of depression in remission. Furthermore, previously depressed participants whose positive mood increased in response to the happy mood induction showed a poorer level of performance on the task, similar to that observed in the never-depressed group. Thus, a happy mood may have induced a somewhat less accurate, but perhaps more adaptive, approach to processing social information. These findings were robust after controlling for current level of depression and anxiety symptoms, intensity of response to the mood induction, response times, and performance on a control task.

Keywords:

• Depression
• Theory of mind
• Remission
• Mood induction

Acknowledgements

This research was supported by New Opportunities Grants from the Canada Foundation for Innovation to KH, JJ and MS. We are grateful to Kelly Anthony-Brown, Stephanie Dobrowolski, and Lindsey Lytle for their help with data collection and data management.

Notes

¹The deleted items included (distracter adjectives in brackets): 3. Desiring (joking, convinced, flustered); 6. Fantasising (aghast, impatient, alarmed); 10. Cautious (insisting, bored, aghast); 21. Fantasising (embarrassed, confused, panicked); 25. Interested (panicked, incredulous, despondent); 29. Reflective (impatient, aghast, irritated); and 31. Confident (joking, dispirited, ashamed). We conducted our primary analysis using the full 36-item Eyes task to determine whether deleting the 8 non-reliable items from the Eyes task had an effect on our results. Fully consistent with the results reported below, the model revealed a main effect of Depression Group, F(1, 81) = 7.84, p<.01, η²=.09, and a three-way interaction of Group, Condition, and Mood Response Index, F(1, 81) = 6.12, p<.05, η²=.07.

²Although no one in our sample met even subthreshold criteria for a current major depressive episode based on the SCID interview, both groups reported surprisingly high symptom scores. To statistically address the possibility that high depression symptom scores may have affected performance on the Eyes task differentially for the past-depressed and never-depressed groups, we re-ran all of our main analyses excluding participants with BDI-II scores above 13 (i.e., the stated cut-off for mild depression severity; Beck et al., 1996). Our results were robust. Results of these analyses are available from the first author on request.

³Eyes-task performance was also significantly related to AD and GD scores, and the depression groups differed significantly on these two symptom scales. However, we were unable to include these scales as covariates in our full model with BDI-II scores because the three symptom scales were highly correlated (all rs>.62). Therefore, we ran two additional models, controlling, respectively, for AD and GD scores instead of BDI-II scores. The pattern of obtained results in these two additional models were identical to those in the main text. In the model controlling for AD we obtained a main effect of Depression Group, F(1, 81) = 6.97, p<.01, η²=.08, and a three-way interaction of Group, Condition, and Prime Response Index, F(1, 81) = 6.83, p<.05, η²=.08. Similarly, in the model controlling for GD we obtained a main effect of Depression Group, F(1, 81) = 7.94, p<.01, η²=.09, and a three-way interaction of Group, Condition, and Prime Response Index, F(1, 81) = 6.73, p<.05, η²=.08.

⁴Results of these analyses are available from the first author on request.