Background: Alexithymia is a clinically relevant personality trait related to difficulties in recognizing and describing emotions. Previous studies examining the neural correlates of alexithymia have shown mainly decreased response of several brain areas during emotion processing in healthy samples and patients suffering from autism or post-traumatic stress disorder. In the present study, we examined the effect of alexithymia on automatic brain reactivity to negative and positive facial expressions in clinical depression.
Methods: Brain activation in response to sad, happy, neutral, and no facial expression (presented for 33 ms and masked by neutral faces) was measured by functional magnetic resonance imaging at 3 T in 26 alexithymic and 26 non-alexithymic patients with major depression.
Results: Alexithymic patients manifested less activation in response to masked sad and happy (compared to neutral) faces in right frontal regions and right caudate nuclei than non-alexithymic patients.
Conclusions: Our neuroimaging study provides evidence that the personality trait alexithymia has a modulating effect on automatic emotion processing in clinical depression. Our findings support the idea that alexithymia could be associated with functional deficits of the right hemisphere. Future research on the neural substrates of emotion processing in depression should assess and control alexithymia in their analyses.
Keywords: Alexithymia; Automatic processing; Depression; Facial expression; Functional magnetic resonance imaging.