Introduction Theory of Mind is the ability to attribute mental states to others. Investigations have distinguished implicit and explicit forms of ToM. It is known, that patients with schizoprenia have deficits in their explicit ToM, and they also show altered brain activations during examining explicit ToM. Objectives In this study our aim was to investigate the underlying neural substrates of implicit ToM in patients with schizophrenia with fMRI. Methods Seven healthy subjects and two patients with first episode schizophrenia were involved. We used: false belief condition and control condition. All movies consisted of a belief formation phase and an outcome phase. The belief formation phase started with an agent placing a ball on a table in front of an occluder. Then the ball rolled behind the occluder. The movies could continue in different ways leading to a true or false belief. At the end of each movie, the agent reentered the scene and the occluder was lowered. In the outcome phase the ball was either present or absent behind the occluder. The control conditions started with a ball rolled behind the occluder on a table ended up with two different ways as the ball was either present or absent behind the occluder. There was no agent in the control movies. Results We found that healthy subjects activated significantly stronger the left lingual gyrus as well as the right temporoparietal junction. Conclusions Our findings suggest deficits in implicit ToM in schizophrenia and our findings also might help to clarify the underlying neural substrates of implicit ToM. Disclosure This research project was supported by the KTIA-13-NAP-A-II/12 (2018–2022) and the Hungarian National Excellence Centrum Grant 2018–2019.

Introduction Everyday social interactions are based on Theory of Mind (ToM) or mentalizing, whose complex processes are involved in understanding, representing one’s own and other people’s mental states. ToM is supposed to have two systems. The implicit ToM seems to be a fast, automatic, non-verbal processing. The explicit ToM is characterized by a slower, but more flexible processing, which is mostly verbal, interpretative. Several studies have described explicit ToM deficit in schizophrenic patients. Less research has investigated implicit ToM in patients, however recently, there has been a growing number of articles examining implicit ToM of patients with schizophrenia. Objectives The aim of our systematic review and meta-analysis is to summarize the results of the implicit ToM in schizophrenia. Methods A systematic search was performed in four major databases. We included 11 publications. 7 studies; and 5 studies were included the quantitative synthesis and the qualitative synthesis, respectively. Results We found significant differences in accuracy, reaction time and brain activation patterns during implicit ToM between schizophrenic patients and controls. The systematic review revealed further alterations in visual scanning, cue fixation, face looking time, and difficulties in perspective taking. Conclusions Based on our results implicit ToM is affected in schizophrenia in addition to explicit ToM deficit. However, based on these results we cannot exclude the possibility, that implicit ToM or at least some elements of it might be relatively unaffected (e.g. detection of intentionality), however its effectiveness is limited by non-mentalizing deficits (e.g. certain neurocognitive impairments). Our results may have important implications for the remediation of mentalizing skills. Disclosure The research is supported by the Hungarian National Excellence Centrum Grant (FIKP II) and Hungarian Brain Research Program (KTIA-13-NAP-A-II/12).