For patients with major depressive disorder (MDD), impaired cognitive control may exacerbate worry which negatively relates to aversive emotional states and maintenance of MDD. These findings were published in the International Journal of Psychophysiology.
Patients (n=36) with MDD were recruited from the County Hospital of Hall in Tirol in Austria, local psychotherapists, psychosocial counseling centers, and support groups and healthy controls (n=36) were recruited within the community. Study participants were assessed for autonomic cardiovascular regulation using a breathing focus task and electrocardiogram, severity of depression using the Beck Depression Inventory (BDI-II), and worry using the Penn State Worry Questionnaire (PSWQ).
The patients and controls were aged mean 38.19 (standard deviation [SD], 12.13) and 36.58 (SD, 12.67) years and heart rate was 77.72 (SD, 9.93) and 75.31 (SD, 12.05) bpm, respectively.
During the resting period, heart rate variability (HRV) was lower among patients with MDD in both high (F[1,70], 4.53; P =.037) and low (F[1,70], 4.55; P =.036) frequencies.
Among all participants, high and low frequency power decreased during worry and was higher during the pre- and postworry breathing focus task. Overall, patients with MDD exhibited lower HRV.
Respiratory rate did not differ between cohorts (F[1,70], 1.69; P =.20) and patients with MDD reported focusing on their breathing less frequently (F[1,70], 35.58; P <.001).
Higher PSWQ scores associated with greater worry in MDD compared with controls (F[1,70], 178.96; P <.001).
During the pre-worry phase, patients with MDD reported more neutral (mean, 3.22 vs 1.92) and negative (mean, 2.42 vs 0.15) thought intrusions and fewer positive intrusions (mean, 0.72 vs 1.00). Similar trends were reported during the postworry phase. MDD associated with more intrusions overall (F[1,70], 34.89; P <.001).
Patients with MDD reported more negative mood (F[1,70], 55.03; P <.001) and their mood decreased during the study intervention among both patients and controls (F[1,70], 8.97; P =.004). Patients reported increased perceived stress during the worry period (F[1,70], 7.72; P =.007).
Before the worry phase, low frequency HRV was significantly correlated with negative intrusions (r, -0.22; P <.05) and mood rating (r, 0.28; P <.01) and PSWQ was correlated with neutral intrusions (r, 0.30; P <.01), negative intrusions (r, 0.60; P <.01), and mood rating (r, -0.63; P <.01). After the worry phase, PSWQ score was correlated with breathing focus (r, -0.63; P <.01), neutral intrusions (r, 0.41; P <.01), negative intrusions (r, 0.52; P <.01), and mood rating (r, -0.56; P <.01).
This study was limited by not controlling for the effects of medication.
“In conclusion, this study provided evidence of reduced parasympathetic cardiac control at rest and during a breathing focus task in patients with MDD. The behavioral results of the task suggest less success in terms of breathing focus, associated with more frequent negative and neutral thought intrusions; moreover, the patients reported greater stress and aversive mood during the task. […] Impaired cognitive control may exacerbate worry, which in turn is involved in the genesis of aversive emotional states and maintenance of MDD,” stated the study authors.
Bair A, Marksteiner J, Stöcklein T, Reyes del Paso GA, Duschek S. Parasympathetic cardiac control during attentional focus and worry in major depressive disorder. Int J Psychophysiol. 2022;177:1-10. doi:10.1016/j.ijpsycho.2022.04.008