Evidence of dysregulated affect indicated by high alexithymia in obstructive sleep apnea

Alexithymia refers to dysregulation of affect characterized by difficulty in identifying and expressing emotions. Obstructive sleep apnea (OSA) is characterized by increased medical/psychiatric comorbidity and possibly by affect dysregulation. In the present case-control study, we examined alexithymia levels with the Toronto Alexithymia Scale (TAS-20) in 23 psychiatrically uncomplicated OSA outpatients and 23 same gender controls one-to-one matched for age, education and subjective depressive symptomatology. General health/quality of life was assessed with the Short-Form 36 Health Survey (SF-36) in the patient group. Hierarchical multivariate regression models were used to evaluate the association of alexithymia with the presence of OSA, and clinical and polysomnographic parameters of this condition. TAS-20 total and subscale scores were associated positively with Beck Depression Inventory (BDI)-21 and negatively with SF-36 scores. After adjusting for all confounders, OSA was positively associated with total TAS-20 score, 'expressing feelings' and 'externally oriented thinking' subscales. The latter was associated with increased sleepiness and reduced blood oxygenation in the OSA group. Finally, 'difficulty describing feelings' and 'externally oriented thinking' significantly predicted risk for OSA. Alexithymia is higher in non-psychiatrically ill patients with OSA compared with carefully matched controls even after adjustment for subjective depressive symptoms and demographic confounders. Total alexithymia is associated with greater subjective depression and poor general health/quality of life, while 'externally oriented thinking' is associated with disease severity and together with 'difficulty describing feelings' may be vulnerability factors for OSA, although reverse causality cannot be excluded.