J Psychiatry Neurosci 2015;40(2):118-125
Paul Roux, MD, PhD; Christine Passerieux, MD, PhD; Franck Ramus, PhD
Background: Schizophrenia has been characterized by an impaired attribution of intentions in social interactions. However, it remains unclear to what extent poor performance may be due to low-level processes or to later, higher-level stages or to what extent the deficit reflects an over- (hypermentalization) or underattribution of intentions (hypomentalization).
Methods: We evaluated intentional motion perception using a chasing detection paradigm in individuals with schizophrenia or schizoaffective disorder and in healthy controls while eye movements were recorded. Smooth pursuit was measured as a control task. Eye-tracking was used to dissociate ocular from cognitive stages of processing.
Results: We included 27 patients with schizophrenia, 2 with schizoaffective disorder and 29 controls in our analysis. As a group, patients had lower sensitivity to the detection of chasing than controls, but showed no bias toward the chasing present response. Patients showed a slightly different visual exploration strategy, which affected their ocular sensitivity to chasing. They also showed a decreased cognitive sensitivity to chasing that was not explained by differences in smooth pursuit ability, in visual exploration strategy or in general cognitive abilities.
Limitations: It is not clear whether the deficit in intentional motion detection demonstrated in this study might be explained by a general deficit in motion perception in individuals with schizophrenia or whether it is specific to the social domain.
Conclusion: Participants with schizophrenia showed a hypomentalization deficit: they adopted suboptimal visual exploration strategies and had difficulties deciding whether a chase was present or not, even when their eye movement revealed that chasing information had been seen correctly.
Submitted Feb. 26, 2014; Revised May 20, 2014; Accepted June 17, 2014; Early-released Sept. 23, 2014.
Acknowledgments: This work was supported by Agence Nationale de la Recherche (ANR-09-BLAN-0327, ANR-11-IDEX-0001-02 PSL* and J Psychiatry Neurosci 2015;40(2) 125 ANR-10-LABX-0087) and Assistance Publique — H?pitaux de Paris– Centre National de la Recherche Scientifique (APHP–CNRS). We thank the psychiatrists at Versailles hospital for their help in recruiting patients. We are also grateful to the members of the Laboratoire de Sciences Cognitives et Psycholinguistique for the recruitment of control participants and for their assistance with eye-tracking data collection and processing. Results were presented in a poster at the 2013 Cognitive Neuroscience Society held in San Francisco, Apr. 13–16.
Affiliations: From the Laboratoire de Sciences Cognitives et Psycholinguistique, UMR 8554, CNRS-ENS-EHESS, Institut d’études de la cognition, Ecole Normale Supérieure, Paris, France (Roux, Ramus); Service Universitaire de Psychiatrie d’adultes, Centre Hospitalier de Versailles, Le Chesnay, France (Roux, Passerieux); Université Versailles Saint Quentin en Yvelines, Versailles, France (Roux, Passerieux)
Competing interests: None declared.
Contributors: All authors designed the study. P. Roux acquired and analyzed the data, which F. Ramus also analyzed. P. Roux and F. Ramus wrote the article, which all authors reviewed and approved for publication.
Correspondence to: P. Roux, Service Universitaire de Psychiatrie d’adultes, Centre Hospitalier de Versailles, 177 rue de Versailles, 78157, Le Chesnay, France; firstname.lastname@example.org