Transdiagnostic Expression of Interoceptive Abnormalities in Psychiatric Conditions

Background: Interoception, the sense of internal bodily physiology, influences our thoughts and feelings. Interoceptive dysfunction is implicated in some psychiatric disorders. We undertook a systematic characterisation to determine if abnormalities in cardiac interoception underlie symptoms and diagnoses in patients accessing mental health services. Methods: This cross-sectional study recruited 306 patients (clinical diagnoses spanning affective disorders, personality disorder, and psychoses) and 67 controls. We recorded measures of cardiac physiology (heart rate and heart rate variability; HRV); objective interoceptive influences on perception, and subjective (self-report) sensitivity to interoceptive signals. Outcomes: Patients differed from controls in; 1) HRV (RMSSD ms, patients vs controls mean ± SD: 51.6; ± 42.6 vs 70.19 ± 58.4, [F(1,341)=8.8, P=0.003]); 2) cardiac afferent effects on processing emotional stimuli ([fear - neutral] x [systole - diastole] %intensity change: 5.2 ± 16.1 vs 10.5 ± 16.1, [F(1,324)=4.8, P<0.03]); 3) heartbeat discrimination accuracy (0.52 ± 0.1 vs 0.57 ± 0.2, [F(1,331)=4.8, P=0.03]), and heartbeat detection confidence (VAS mean ± SD: 4.2 ± 2.6 vs 5.4 ± 1.8, [F(1,332)=8.82, P=0.003]). Anxiety and depression scores correlated particularly with subjective interoception (Body Perception Questionnaire-awareness; depression: R=0.34, P<0.001; trait anxiety: R=0.39, P<0.001). Differences between clinical diagnoses were observed for HRV (F(6,234)=3.3, P=0.004), cardiac afferent effects on processing emotional stimuli (F(6,234)=3.1, P=0.006) and subjective interoception (F(6,236)=2.4, P=0.03). Patients with schizophrenia showed distinct differences that merit further investigation. Interpretation: Interoceptive differences in patients relate to psychiatric symptoms and diagnoses, highlighting value in developing interoceptive targets for therapeutic intervention. Trial Registration: ISRCTN13588109. Funding Statement: The study was supported by an Advanced Grant from the European Research Council to HDC: Cardiac control of Fear in the Brain CCFIB 324150. Declaration of Interests: The study was supported by an Advanced Grant from the European Research Council to HDC. HH-B was a medical student at the time of involvement with the study. Other authors were employees of Brighton and Sussex Medical School, University of Sussex at the time of the study. Ethics Approval Statement: The study was approved by the National Research Ethics Service (13/LO/1866MHRNA).