Background. The Temperament and Character Inventory (TCI) by Cloninger is a widely used instrument to measure personality dimensions. Two dimensions of the TCI, Harm avoidance (HA) and Self-Directedness (SD), are known to be influenced by depressed mood. This study investigated changes in HA and SD after 10 weeks of Internet-delivered cognitive behavior therapy (ICBT) in a sample of clinically depressed subjects (N = 108). Differences in personality changes among treatment responders and non-responders were also investigated. Exploratory investigations on changes for other TCI dimensions, were also conducted. Methods. Depressed subjects were randomized either to ICBT or to a moderated online discussion group, which served as an active control group. The interventions lasted for 10 weeks. TCI was measured at baseline and after treatment. Depressive symptoms were assessed using the Beck Depression Inventory-II. Results. There were significant changes on HA and SD after ICBT. However, when comparing post-treatment HA and SD to the control, no differences were found. Among responders, larger changes compared to non-responders were found in HA and in SD, as well as in Cooperativeness. Conclusions. The study showed that HA and SD changed after ICBT. The changes in personality seem related to improvement in depression rather than a direct effect of ICBT.
Keywords: Character; Cognitive behavior therapy; Depression; Internet; Personality; TCI; Temperament.