Stability of alexithymia in the general population: an 11-year follow-up

There is an ongoing debate concerning the temporal stability of alexithymia. Most previous studies have been conducted on clinical populations of psychiatric and somatic patients. However, psychiatric and somatic morbidity have been found to confound the findings so that in their presence, alexithymia appears to be less stable. Nevertheless, few general population studies have been published, and there have been no follow-ups longer than 5 years.

In a population-based sample of middle-aged Finnish men, 755 participants completed the Toronto Alexithymia Scale (TAS)-26 at baseline and on 11-year follow-up. Absolute or mean stability refers to the extent to which scores change over time, and it was measured with group comparisons of paired samples. Relative stability refers to the consistency of relative differences in alexithymia levels among the study subjects, and it was measured with test-retest correlations.

Changes in the total scores and the subscales of the TAS-26 were all statistically significant but had low effect sizes (0.09-0.20) for the change-suggested absolute stability. The correlations between baseline and follow-up scores were high (ρ = 0.51-0.63), indicating relative stability. The exclusion of depressive symptoms, a history of mental illnesses, and cancer or cardiovascular diseases at baseline and at the 4- and 11-year follow-ups did not essentially alter these findings. Of the background variables, a higher age independently associated with the increase in the TAS-26 scores. Those with alexithymia at baseline were more likely to have elevated depressive symptoms at the 4- and 11-year follow-ups.

Both the absolute and relative stabilities of alexithymia in the general population are high, even for a long follow-up period. These results may support the assumption that alexithymia represents a stable personality trait in general. Alexithymia may increase vulnerability to depressive symptoms.