Theory of mind in patients with schizophrenia: is mentalizing delayed?

Objective: Functional imaging studies have used numerous neurocognitive designs to investigate brain activation during theory of mind (ToM) tasks in patients with schizophrenia. The majority of studies asks participants to retrospectively attribute mental states to others. We used a novel animated task to investigate implicit mentalizing online. Because behavioral studies have revealed slower ToM performance reaction times in patients with schizophrenia, we hypothesized that time would influence functional MRI (fMRI) activation patterns also.

Methods: We applied the "Moving Shapes" paradigm, which involves two interacting triangles, to a functional MRI block design and investigated the neural activation patterns of 15 patients with schizophrenia and 14 healthy controls. We additionally analyzed the first and second halves of each video separately to assess time-related differences.

Results: Overall, patients with schizophrenia showed increased activation in the inferior and middle frontal gyri, the superior temporal gyrus, the precuneus and the cerebellum compared with controls during ToM versus non-ToM videos. Most importantly, patients with schizophrenia had predominantly increased activation in ToM-related brain areas during the second half of the ToM paradigm, whereas the activation in areas of the ToM-network in healthy controls occurred during the first half of the presentation.

Conclusions: Our results confirm recent findings of significantly stronger neural activations that encompass the fronto-temporo-parietal cerebral areas in patients with schizophrenia compared with controls during ToM tasks. The observation of slower cognitive processing in patients with schizophrenia during mentalizing might explain some of the contradictory imaging findings in these patients and have implications for cognitive remediation.