Interoception, Somatic Symptoms, and Somatization Tendency in Chinese Individuals with Subsyndromal Depression: A Follow-Up Study.

Interoception refers to the sensation and perception of internal bodily sensations, and may be related to depressive symptoms. Schemata concerning the body vary across different cultures and may influence interoception and symptom presentations of depression. This study explored the relationship between interoception, depressive symptoms, and schema of somatic focus in Chinese people with subsyndromal depression. Thirty-nine individuals with subsyndromal depression (SD) and 40 healthy controls (HCs) were assessed at baseline and after 3 months. Participants completed the self-report questionnaires for assessing interoceptive sensibility, somatic and psychological symptoms of depression, and somatization tendency. They also completed the heartbeat perception behavioral task for estimating interoceptive accuracy. The results showed that both the SD and the HC groups showed similar interoceptive accuracy, although the SD group showed heightened interoceptive sensibility. The discrepancy between interoceptive sensibility and interoceptive accuracy is termed the interoceptive trait prediction error (ITPE). The ITPE was positive in SD participants but was negative in HCs. In the entire sample, interoceptive sensibility and the ITPE were correlated with somatic symptoms rather than with psychological symptoms of depression. Interoceptive sensibility partially mediated the relationship between somatization tendency and somatic symptoms, after controlling for psychological symptoms of depression. These results remained stable after 3 months. The shortcomings of the present study were a lack of clinical interview to ascertain diagnosis and a short follow-up duration. In conclusion, our study suggests that altered interoception occurs in subsyndromal depression. Interoception is related to somatic symptoms of depression. The schema of body was related to depressive symptoms, partially through interoception, in Chinese people with subsyndromal depression.