Alexithymia and self-directedness as predictors of psychopathology and psychotherapeutic treatment outcome

Objective: Alexithymia, a common personality style of patients seeking psychotherapeutic help, is associated with illness severity and negative treatment outcome in various mental disorders. Still, it remains unclear how alexithymia influences psychopathology and the therapeutic processes. In previous studies, a strong association of alexithymia with self-directedness (SD), a dimension of Cloninger's Temperament and Character Inventory (TCI) has been shown. In this study, we investigated the interaction of alexithymia and SD, and their impact on general psychopathology and on treatment outcome.

Method: 716 consecutively admitted day-clinic outpatients were examined at admission (t0) and discharge (t1). The Toronto Alexithymia Scale 20 (TAS-20), the SD subscale of the TCI and the Symptom Checklist 90 (SCL-90-R) were administered. Linear regression analyses were performed to calculate associations and the predictive power of TAS-20 and SD on psychopathology at admission and treatment outcome. ANOVA was used to calculate interactions of TAS-20 and SD on treatment outcome. A general linear model was applied to compare the outcome of four subgroups, defined by high/low TAS-20 and SD scores.

Results: Regression analyses revealed significant prediction of the baseline General Severity Index (GSIt0) by TAS-20 (df=4, 711; Beta: 0.385; p<0.001) and SD (Beta: -0.365; p<0.001). The whole model accounted for 41% of the explained variance. On subscale level, the 'Difficulties in identifying feelings' facet (DIF) of TAS-20 was the strongest predictor of GSIt0 (Beta: 0.478, P<0.001) and GSIt1 (Beta: 0.072, p=0.049). Therapeutic outcome measured by GSIt1 was significantly predicted by SD (df=5, 710; Beta: -0.065; p=0.041), but not by TAS-20 (Beta: 0.042; p=0.179). Change scores (∆) of TAS-20 and SD predicted GSIt1 (df=5, 710; TAS-20∆ Beta: -0.268; p<0.001; SD∆ Beta: 0.191; p<0.001) as well as GSI∆ (df=5, 710; TAS∆ Beta: 0.384; p<0.001; SD∆: -0.274; p<0.001) significantly. ANOVA revealed no significant interactions of TAS-20 and SD at admission on the treatment outcome (p>0.05).

Conclusion: Low SD was shown to be a common problem of alexithymic patients and both, alexithymia and SD were highly associated with general symptom severity. SD was found to have a greater impact on treatment outcome while adjusting for baseline GSI. Alexithymia and SD act as independent factors with no significant interaction in their impact on psychopathology at admission and discharge. As different interventions were shown to improve SD scores in previous studies, SD may represent a relevant psychotherapeutic target, worthy to be addressed especially in alexithymic patients. Future studies should investigate other dimensions of the TCI, especially harm avoidance and reward dependence.