Research consistently has evidenced the association among alexithymia, somatosensory amplification (SA) and functional somatic symptoms (FSS). Yet, the underlying mechanism of such relationship has not been explored among Chinese adolescents. This study aims to evaluate whether SA exerts a moderating or mediating effect on the alexithymia-FSS link.

Analyses were based on 269 adolescents with mild to severe depressive symptoms (Center of Epidemiological Studies—Depression Scale (CES-D)>15) recruited from a school-based study. They completed the Somatosensory Amplification Scale (ChSAS), the Somatic symptom subscale of CES-D and the Toronto Alexithymia Scale-Short form (TAS-9-C). Three facets of alexithymia (difficulty identifying feelings (DIF), difficulty describing feelings (DDF) and externally-oriented thinking (EOT)) were force-entered in each univariate regression model. Facets of alexithymia that were found significant (p < 0.05) were subsequently included in regression models to test the mediating and moderating effects of SA on FSS.

Results of hierarchical regression analysis found that both DIF (standardized β = 0.37, p < 0.001) and DDF (standardized β = 0.12, p = 0.043) were significant predictors of somatic symptoms. A moderate mediating effect was observed for SA on the DIF-somatic symptoms (Sobel test z = 2.13, p = 0.03). The results also showed a significant moderating effect of DIF×SA on somatic symptoms (standardized β = 0.49, p < 0.001).

SA qualifies as a mediator and a moderator between alexithymia and FSS. It indicated that adolescents with alexithymia are likely to report more FSS due to the tendency to amplify their somatic sensation. These results suggest that alexithymia-specific psychotherapeutic methods should be further developed using emotional validation and processing techniques.