Theory of mind in dysphoric and non--dysphoric adults: An ERP study of true-- and false--belief reasoning.

Theory of mind (ToM) - the understanding that others' behaviors are connected with internal mental states - is an important part of everyday social cognition. There is increasing behavioral evidence that ToM reasoning can be affected by mood. To gain insight into the ways sad mood may affect the underlying mechanisms of ToM reasoning, we recorded event-related brain potentials (ERPs) as dysphoric (N = 16) and non-dysphoric (N = 24) participants reasoned about a protagonist's true or false beliefs about an object's location. Results showed significant group effects on early components of the ERP - individuals in the dysphoric group showed greater amplitudes for the anterior N1 and N2/P2 components relative to those in the non-dysphoric group. Later in the ERP, non-dysphoric individuals showed evidence of neurocognitive dissociations between true and false belief. Dysphoric individuals, however, did not show evidence for these later dissociations. This evidence suggests that dysphoria may be associated with effortful reasoning about other's mental states, even when that effort is not necessary (i.e., when reasoning about true beliefs). We discuss the implications of these findings for understanding how mood affects ToM reasoning and for how especially deliberative ToM processing in dysphoria may lead to social difficulties.