Insights from a laboratory and naturalistic investigation on stress, rumination and frontal brain functioning in MDD: An fNIRS study

Abstract

Recent research has emphasized rumination as an important maintaining factor in various mental disorders. However, operationalization and therefore induction of rumination in experimental settings poses a major challenge in terms of ecological validity. As stress seems to play a key role in everyday situations eliciting rumination, we conducted two stress paradigms while assessing behavioral and neurophysiological measures. Aiming to replicate previous findings on induced rumination by means of the Trier Social Stress Test (TSST) and comparing them to physiological (pain) stress, a clinical sample of patients with Major Depressive Disorder (MDD; n = 22) and healthy controls (HC; n = 23) was recruited. Cortical blood oxygenation was assessed during the stress paradigms using functional near-infrared spectroscopy (fNIRS). Further, we used ecological momentary assessment (EMA) of stress, rumination and mood to be able to correlate ruminative responses during induced stress and everyday rumination. Our results showed that social stress but not physiological stress induced depressive rumination in MDD but not in HC. Further, rumination reactivity in response to social stress but not to physiological stress was significantly associated with rumination reactivity in everyday life as assessed with EMA. With respect to cortical oxygenation, MDD subjects showed hypoactivity in the Cognitive Control Network during the TSST, which mediated the differences between MDD and HC in post-stress rumination. Our findings emphasize the role of negative social triggers in depressive rumination and validate the TSST as an induction method for depressive rumination. The results inform future developments in psychotherapeutic treatment for depressive rumination.

Keywords: Major Depressive Disorder; Repetitive negative thought; Rumination; Socially Evaluated Cold-Pressor Test (SECPT); Trier Social Stress Test (TSST); functional near-infrared spectroscopy (fNIRS).

Fig. 1

Time course of the TSST. BADO = Social Demographic Data, BDI = Beck Depression Inventory II, RRS = Rumination Response Scale, FEEL-E = Questionnaire to assess emotion regulation strategies, LSAS = Liebowitz Social Anxiety Scale, PANAS = Positive and Negative Affect Schedule, VAS = Visual Analogue Scale assessing the subjective stress ratings, SRQ = state rumination questionnaire, RSQ = resting-state questionnaire, CTL1 = Control Task 1/reading numbers, CTL2 = Control Task 2/calculations without social stress. BADO, BDI and RRS were only assessed at the first measurement date, FEEL-E and LSAS at the second measurement date. Participants got debriefed only after completion of both measurements.

Fig. 2

Time course of the SECPT. BADO = Social Demographic Data, BDI = Beck Depression Inventory II, RRS = Rumination Response Scale, FEEL-E = Questionnaire to assess emotion regulation strategies, LSAS = Liebowitz Social Anxiety Scale, PANAS = Positive and Negative Affect Schedule, VAS = Visual Analogue Scale assessing the subjective stress ratings, SRQ = state rumination questionnaire, RSQ = resting-state questionnaire. BADO, BDI and RRS were only assessed at the first measurement date, FEEL-E and LSAS at the second measurement date. Participants got debriefed only after completion of both measurements.

Fig. 3

Cortisol and heart rate in response to the TSST and SECPT. Heart rate in beats per minute (bpm) dependent on condition and group in the TSST (A.1/2) and the SECPT (B.1/2). Error bars indicate standard errors. *p < .05, **p < .01,***p < .001. CTL = control task, anti = anticipation phase, inter = job interview, arit = arithmetic task, rest = resting state.

Fig. 4

Subjective stress ratings assessed with the Visual Analogue Scale (VAS) dependent on condition and group in the TSST (A) and SECPT (B). Error bars indicate standard errors. *p < .05, **p < .01,***p < .001, comparisons in both graphs are related to differences between time points.

Fig. 5

Negative affect assessed by the PANAS dependent on condition and group in the TSST (A.1) and SECPT (B.1). State rumination dependent on condition and group in the TSST (A.2) and SECPT (B.2). Error bars indicate standard errors. *p < .05, **p < .01,***p < .001.

Fig. 6

Boxplots indicating the percentage of triggers of rumination over the two weeks of EMA assessment dependent on group (MDD = depressed patients, HC = healthy controls). Note that only the three triggers significantly differing in their occurrence between the groups were depicted. No events = average number of reporting no stressful event per subject, interactions = average number of social interactions that led to stress per subject, internal = average number of internal events (e.g. thoughts, emotions) that led to the experience of stress per subject.

Fig. 7

Correlation of the TSST- (A) and SECPT- (B) related increases in state rumination and daily rumination reactivity. Confidence bands indicate standard errors.

Fig. 8

Differences between MDD and HC during control task 1 (CTL1 = reading numbers), control task 2 (CTL2 = performing calculations without social stress) and TSST (arithmetic challenge). Cool colors indicate reduced O2Hb-levels in the MDD group as compared to the HC group; warm colors vice versa. Differences are depicted in Cohen's d. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)