Transdiagnostic expression of interoceptive abnormalities in psychiatric conditions

<jats:p>Background: Interoception, the sensing of information about the internal physiological state of the body, is proposed to be fundamental to normal and abnormal affective feelings. We undertook a cross-sectional characterisation of cardiac interoception in patients accessing secondary mental health services to understand how interoceptive abnormalities relate to psychiatric symptoms and diagnoses. Methods: Patients attending adult mental health services (205 female, 101 male) and controls (42 female, 21 male) participated. Clinical diagnoses spanned affective disorders, personality disorders and psychoses. Physiological, bio-behavioural and subjective interoceptive measures included: 1) Basal heart rate and heart rate variability (HRV); 2) cardiac afferent effects on emotional processing (cardiac cycle modulation of ratings of fear vs. neutral faces); 3) perceptual accuracy, confidence, and metacognitive insight in heartbeat detection, and; 4) self-reported sensitivity to internal bodily sensations. We tested for transdiagnostic differences between patients and controls, then for correlations between interoceptive measures and affective symptoms, and for group differences across clinical diagnostic categories. Results: Patients differed from controls in HRV, cardiac afferent effects on emotional processing, heartbeat discrimination accuracy, and heartbeat detection confidence. Anxiety and depression symptom severity correlated particularly with self-reported sensitivity to interoceptive experiences. Significant differences between diagnostic categories were observed for HRV, cardiac afferent effects on emotional processing, and subjective interoception. Patients with schizophrenia relative to other diagnoses intriguingly showed opposite cardiac afferent effects on emotion processing. Conclusions: This multilevel characterisation identified interoceptive differences associated with psychiatric symptoms and diagnoses. Interoceptive mechanisms have potential value for the clinical stratification and therapeutic targeting of psychiatric disorders.</jats:p>