Self-face recognition and theory of mind in patients with schizophrenia and first-degree relatives
Introduction
Deficits in social function are profound in schizophrenia and its spectrum disorders. Impairments include difficulties in communication, establishing and maintaining interpersonal relationships, self-care, and fulfilling family and occupational roles. Efforts to identify variables that contribute to social skill impairments have focused on social cognition, which involves processing of social information toward determining intentions and dispositions of others. ‘Theory of mind’ (ToM) is an aspect of social cognition that has recently received attention as potentially underlying the social dysfunction in schizophrenia.
ToM is the ability to conceptualize other people's mental states in order to explain and predict their behavior (Premack and Woodruff, 1978). Capacity for ToM allows individuals to engage in adaptive, introspective social behaviors/strategies (reviewed in Corcoran, 2001). It has been viewed as an essential component for both self-reflection and coordinated social actions (Leudar et al., 2004). The etiology and nature of ToM deficits is unclear and may relate to genetic, personality and social factors (Doody et al., 1998).
ToM impairments have been well established in disorders of social dysfunction, such as autism and Asperger's syndrome (Baron-Cohen et al., 1985, Baron-Cohen et al., 2000, Frith, 2001). Frith (1992a,b) initially postulated that certain symptoms of schizophrenia reflect difficulty appreciating other's mental states leading to social withdrawal, inappropriate behaviors and changes in affect. There is ample support for ToM based deficits in schizophrenia (for reviews, see Brune, 2005, McCabe, 2004, Pinkham et al., 2003).
The pattern of deficiency on ToM tasks also appears to be paralleled, albeit to a lesser degree, in people with schizotypal personality traits (Kremen et al., 1998, Langdon and Coltheart, 1999, Langdon and Coltheart, 2001, Pickup and Frith, 2001, Platek et al., 2003a, Platek and Gallup, 2003, Platek and Gallup, 2002, Platek et al., 2004b). Deficits in healthy first-degree relatives of patients with schizophrenia would suggest that ToM performance is genetically influenced and a putative endophenotype (see Gershon and Goldin, 1986, Gottesman and Gould, 2003). Two family studies report conflicting findings (Janssen et al., 2003, Kelemen et al., 2004). Neither accounted for the potential influence of schizotypal personality traits.
Self-recognition, a measure of self-processing, may be a prerequisite for the ability to infer others' mental states (Gallup, 1982, Gallup et al., 2003). This hypothesis is supported by evidence from both humans and animals (e.g. Gallup et al., 2003). For example, only species that demonstrate mirror self-recognition show the ability to make mental state attributions (Gallup, 1985, Gallup et al., 2003, Povinelli et al., 1993). In humans, early forms of ToM develops after capacity for mirror self-recognition by 18–24 months (Baron-Cohen et al., 1985, Baron-Cohen et al., 2000, Flavell, 1999, Lewis and Brooks-Gunn, 1979). Functional neuroimaging has shown that self-recognition and mental state attribution may share a neurocognitive network involving right middle and superior temporal gyri (Platek et al., 2004a, Vogeley et al., 2001). Thus, there appears to be preliminary support for operational, functional and anatomical relationships between ToM and self-recognition.
Hallucinations and thought insertion could be due to misattributions of self-generated stimuli to external sources (Allen et al., 2004, Blakemore et al., 2003, McGuire et al., 1995). Patients with schizophrenia perform poorly on tasks requiring self-recognition (Daprati et al., 1997, Orbach et al., 1966, Traub and Orbach, 1964) and fail to recognize activities such as speech as self-initiated (Daprati et al., 1997, Ford and Mathalon, 2005, Frith, 1992a, Frith, 1992b, Harrington et al., 1989).
While face processing has been investigated in schizophrenia, self-face recognition requires further study. There is mounting evidence that capacity for self-face recognition is distinct from familiar face recognition (Keenan et al., 2000, Platek et al., 2004a, Platek et al., 2005, Sugiura et al., 2000, Sugiura et al., 2001, Sugiura et al., 2005). Patients with schizophrenia are impaired on face processing tasks including judging and labeling facial expressions, recognition memory for unfamiliar faces and recognition of facial identity (for reviews, see Kohler et al., 2003, Mandal et al., 1998). Notably, patients are accurate on familiar face recognition but impaired on unfamiliar face-matching (Archer et al., 1994), suggesting the need for further investigation of the role of familiarity. Furthermore, schizotypal individuals have slower reaction times when responding to self-face than familiar or unfamiliar faces (Platek and Gallup, 2002, Platek et al., 2003b).
The current study utilized a sample of stable, chronic schizophrenia outpatients to further elucidate the relationship between ToM and face recognition. We also tested unaffected first-degree relatives to establish whether deficits in face recognition and ToM may be endophenotypic markers of the social dysfunction in schizophrenia. The impact of schizotypal personality traits on ToM and face recognition was also evaluated.
We hypothesized that (1) patients with schizophrenia would be more impaired than unaffected relatives who would perform worse than controls in making mental state attributions; (2) patients and relatives would be less impaired for familiar faces; (3) schizotypal personality traits would impact performance; and (4) there would be a positive correlation between the self-face recognition task and ToM performance.
Section snippets
Subjects
10 patients with schizophrenia, 10 first-degree relatives of these patients (1 per patient) and 10 healthy controls were recruited from the Schizophrenia Research Center at University of Pennsylvania. Patients were diagnosed following a comprehensive intake evaluation including a psychiatric examination, semi-structured clinical interview, record review and consensus diagnoses among a team of research psychiatrists (Gur et al., 1991). Patients who had one first-degree relative willing to
Sample characteristics
Demographic characteristics and smoking history are presented in Table 1. There were no significant differences on demographic variables, except age (see Table 1). When possible, age was included as a covariate. Except for one relative with a history of depression, relatives had no Axis I disorder.
Modified SPQ validity scales were used to screen for response bias (see Table 2). At most one infrequency item was endorsed by participants, suggesting non-random responses.1
Discussion
Social dysfunctions that are hallmarks of schizophrenia can be investigated using ToM and face recognition based paradigms. The hypothesized link between ToM and face recognition was not supported for reaction times, but there was a significant correlation for accuracy. Those who were more accurate in making mental state attributions correspondingly made more accurate judgments on the face recognition task. The inverse was true for patients who took longer and were less accurate on face
Acknowledgments
This work was made possible by a Michael Smith Doctoral Award for Research in Schizophrenia by the Canadian Institutes of Health Research to the first author and was completed as part of doctoral training. The authors would like to thank Drexel University's Department of Psychology and the University of Pennsylvania's Department of Neuropsychiatry/Brain Behavior Laboratory (BBL). In particular, the assistance of research coordinators at the BBL was appreciated—particularly that of Jennifer
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