Chronically depressed patients show considerably impaired interpersonal features, which could be explained by a reduced Theory of Mind (ToM) ability.

The aim of this study was to examine whether chronically depressed patients are impaired in their ToM performance compared to a healthy control group in three different components of ToM: the social cognitive and social perceptual component as well as the ability to take someone else's visual perspective.

32 chronically depressed patients (DSM-IV) were compared to 32 matched healthy controls. ToM abilities were assessed by a cartoon picture story test (CT), the ‘Perspective task’ (PT) and the ‘Reading the mind in the Eyes’ test (RMET). In addition, information about depression severity, childhood trauma and executive functioning (working and logical memory) was assessed for both groups.

Patients mentalized significantly less frequently than healthy controls in the CT (Mann-Whitney-U=340,50, p<0,05). Furthermore, the CT was significantly correlated with the RMET (patients: r=0,46, p<0,05; controls: r=0,57, p<0,01). We didn’t find any significant difference between both groups in the RMET (p>0,05). In the PT, patients showed significantly lower scores than controls (t(35,68)=2,10, p<0,05). There wasn’t any significant correlation between the three ToM tests and severity of depression, duration of illness or childhood trauma (p>0,05).

Our results suggest that chronically depressed patients show deficits in their social cognitive ToM ability compared to controls, whereas their social perceptual ToM ability seems to be unimpaired. As to the capacity to take someone else's perspective, our results suggest that chronically depressed patients present significant deficits.