Little differences in afferent bodily signals observed between patients with somatoform disorders (SFD) and major depressive disorder (MDD). These findings were published in Psychiatric Research Communications.

Patients with SFD (n=24), MDD (n=24), and healthy controls (n=22) were recruited between 2016 and 2017 at the Ambulante Psychosoziale Rehabilitation in Austria and Schoen Clinic Roseneck in Germany. Study participants were evaluated by the Screening for Somatoform Disorders (SOMS), Beck’s Depression Inventory II (BDI-II), State-Trait-Anxiety Inventory (STAI), Trier Inventory for Chronic Stress (TICS), and for cortisol levels before and after a Socially Evaluated Cold Pressor Test (SECPT) and control intervention.

The SFD, MDD, and controls were aged mean 37.2, 40.9, and 31.1 years (P =.025); the male to female ratio was 4/20, 12/12, and 8/14; and BMI was 24.6, 25.6, and 23.1 kg/m2, respectively.


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Significant group differences were observed for SOMS using the trait (χ2, 17.29; P <.001), SOMS state version (χ2, 13.76; P <.001), BDI-II (χ2, 24.16; P <.001), STAI trait anxiety (χ2, 37.15; P <.001), STAI state anxiety (χ2, 11.36; P <.001), TICS screening scale (χ2, 16.15; P <.001), high frequency heart rate variability (HRV; χ2, 7.48; P =.001), and low frequency HRV (χ2, 6.09; P =.004) at baseline.

During both interventions, heart rate changed significantly among all groups (P =.046), increasing between baseline and minute 1 (P <.001) and decreasing between minutes 2 and 3 (F[3,198], 3.00; P <.001). Diastolic blood pressure increased more strongly during the control intervention (F[3,198], 4.75; P =.017).

Salivary cortisol levels in general increased after the stress intervention (F[6,402], 12.38; P <.001).

Heart beat-evoked potentials were higher during distraction than during the heart beat perception task (F[1,66], 4.28; P =.042) due to higher negativity in the early and late control interval. Conversely, the opposite trend was observed during the normal heart beat-evoked potential interval (F[2,132], 3.79; P =.025).

Interoceptive sensibility was lower in the MDD group (F[2,66], 3.94; P =.024).

Interoceptive accuracy scores were correlated with low frequency heart rate (r, 0.31; P =.009), high frequency heart rate variability (r, 0.27; P =.024), and change in heart beat-evoked potential (r, -0.29; P =.016).

No correlations with SOMS using trait or BDI-II scores were observed.

This study was limited by the baseline group differences.

The study authors concluded, “Based on assumptions of the perception-filter model, SFD patients are characterized by more intense afferent bodily signals (I.), as indicated by higher HR and DBP, as well as lower HRV, than HC individuals, whereas no differences in filter system activity (II.) or perception of cardiac signals (III.) were found.”

Reference

Schulz A, Dierolf AM, Lutz APC, et al. Higher cardiovascular activation, but normal heartbeat-evoked potentials and cardiac interoceptive accuracy in somatoform disorders and major depressive disorder. Psych Res Communications. 2022;3(2):100052. doi:10.1016/j.psycom.2022.100052