Alexithymia and tissue inflammation.

BACKGROUND: Altered immune responses are seen in depression, and recent data suggest that similar changes could also be observable in alexithymia. We examined whether the inflammatory markers high-sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6 are independently related to alexithymia or its factors in a population-based sample.
METHODS: This study formed a clinical part of the Kuopio Depression (KUDEP) general population study focusing on the mental health of a general population of adults aged 25-64 years (n = 308). Alexithymia was measured using the Toronto Alexithymia Scale (TAS-20), and depressive symptoms were assessed using the Beck Depression Inventory (BDI-21).
RESULTS: The levels of IL-6 (in picograms per milliliter) and hs-CRP (in milligrams per liter) were significantly higher in alexithymic than in nonalexithymic subjects (IL-6 effect size, ES: 0.50; hs-CRP ES: 0.27). The BDI scores, hs-CRP and IL-6 explained 33.5% of the variation in TAS scores in the whole study population. According to logistic regression analysis, hs-CRP but not IL-6 increased the likelihood of belonging to the alexithymic group. This observation remained unaltered after additional adjustments for chronic inflammation-related disorders, the use of inflammation-modulating medications and depressive symptoms.
CONCLUSIONS: Our findings suggest that the association between hs-CRP and alexithymia resembles that observed in depressed patients. It is, however, independent of depressive symptoms. These findings widen our view on the stress-alexithymia concept.