Theory of mind deficits in chronically depressed patients
Poor theory of mind (ToM) performance has been found in patients with mood disorders, but it has not been examined in the subgroup of chronic depression where ToM deficits may be even more persistent than in acute depressive episodes. The aim of this study was to compare the ToM performance of chronically depressed patients with a healthy control group and to clarify the relation of ToM to other cognitive functions. ToM performance was assessed in 30 chronically depressed patients and 30 matched healthy controls by two cartoon picture story tests. In addition, logical memory, alertness, and executive functioning were evaluated. Chronically depressed patients were markedly impaired in all ToM- and neuropsychological tasks compared to healthy controls. Performance in the different ToM tests was significantly correlated with at least one other cognitive variable. After controlling for logical memory and working memory, no ToM tasks predicted being a patient. Patients with chronic depression present significant deficits in "reading" social interactions, which may be associated with general cognitive impairments.