Decoding and reasoning mental states in major depression and social anxiety disorder.

Background: Major depression (MDD) and social anxiety (SAD) disorders are debilitating psychiatric conditions characterized by disturbed interpersonal relationships. Despite these impairments in social relationships, research has been limited in simultaneously evaluating the dysfunction in MDD or SAD within two aspects of theory of mind (ToM): decoding mental states (i.e., Affective ToM) and reasoning mental states (i.e., cognitive ToM). Taking this into consideration, the current study assesses both decoding and reasoning mental states abilities in MDD, SAD, and healthy controls (HC).

Methods: Subjects included 37 patients with MDD, 35 patients with SAD, and 35 HCs. ToM was measured with the Reading the Mind in the Eyes Test (RMET) and the Faux Pas Task, which assess decoding and reasoning mental states, respectively.

Results: Results revealed that in decoding of mental states, both the SAD and MDD groups had lower scores than the HC group; there was no significant difference between the SAD and MDD groups in decoding mental states. Conversely, in reasoning mental states, the SAD and HC groups had higher scores than the MDD group; no differences were found between the SAD and HC groups.

Conclusions: Clinicians and researchers should further consider parsing generalized impairment in ToM into two aspects: decoding and reasoning of mental states by using the aforementioned measurements. By further understanding the two aspects, we can create a potentially new clinical profile for mental health disorders, such as in this context with both decoding and reasoning mental state impairment in MDD and just a decoding impairment in SAD.