Is There an Overlap in the Domain of Theory of Mind Between Autism Spectrum Disorders and Schizophenia Spectrum Disorders? Exploring Quailitive Diferences

Background:  

Several recent studies have demonstrated, in addition to genetic overlap (Carroll, 2009), a similarity between autism and schizophrenia in some psychological domains such as theory of mind (ToM) (Spek, 2010). However, at a behavioral level, daily functioning and clinical impression make the two disorders quite different, and they are now considered independent disorders (DSM-IV-TR, ICD-10).  At present, there is a dearth of instruments able to validly distinguish individuals with Asperger’s syndrome from adults with schizophrenia that reflect these subtle differences in ToM. The Movie for the Assessment of Social Cognition (MASC) (Dziobek, 2006) is a promising social cognition instrument that may help differentiating mental state attribution in Asperger and schizophrenia patients. It evaluates ToM through video scripts of four characters interacting in a social situation, and it approximates social interactions as they actually happen in everyday life. Furthermore, it has shown good psychometric properties in English and in Spanish (Lahera, in preparation). In particular, compared with others, this instrument has a dimensional theoretical approach that operationalizes social cognition in a continuum: from mental state inferences that are ‘‘insufficient’’ to mental attributions that are ‘‘too-excessive,’’ paralleling the hypothesis that states that “Psychosis and autism are diametrical disorders of the social brain (Crespi, 2008, 2010).

Objectives:

1. To evaluate ToM in Autism Spectrum Disorders and Schizophrenia Spectrum Disorders
2. To study qualitative ToM deficits in both disorders (undermentalization vs. over-mentalization)
3. To study different psychometrics properties of four different-ToM-instruments in these two clinical-populations

Methods:

After being approved by the Institutional Review Board (IRB) of the Hospital Gregorio Marañón, Madrid, we recruited three groups of participants: twenty participants diagnosed with Asperger’s syndrome and no comorbid disorder (DSM-IV-TR, ADOS-G, IQ > 85), twenty participants with schizophrenia (DSM-IV-TR, K-SADS, SCID-I) treated at Hospital Universitario Gregorio Marañón of Madrid, and twenty healthy volunteers from the same area. In the three groups, the gender distribution was 5 women to 15 men, and the age range was 16-30 years. All groups were matched individually for age, gender, and years of education.

We administered the Frith-Happé animations (Abell, 2000; White, 2011), the Strange Stories (Happé, 1994), the Hinting Task (Corcoran, 1995) and the MASC (Dziobek, 2006) to each participant.

Hypotheses: We expect to find 1) that there is good correlation among the four instruments, with the MASC being the one that discriminates best between the two clinical groups; 2) Despite this, we expect that both clinical groups will be impaired in ToM attributions as measured by all the instruments; and that 3) MASC over-mentalization errors will be significantly higher in the schizophrenia group while under-mentalization errors will be significantly higher in the Asperger group, compared with the healthy-control-group.

Results:

We are currently finishing the evaluations. By May 2013, we will have the final results of the study of these four ToM instruments comparing young individuals with schizophrenia, Asperger’s syndrome, and typical development.

Conclusions:

We expect to find that both groups of disorders have difficulties in tasks of theory of mind, with schizophrenia patients being particularly affected by overmentalization processes and Asperger Syndrome by undermentalization deficits.