Crespi B, Badcock C. Psychosis and autism as diametrical disorders of the social brain. Behav Brain Sci 31: 241-261

Department of Biosciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
Behavioral and Brain Sciences (Impact Factor: 20.77). 06/2008; 31(3):241-61; discussion 261-320. DOI: 10.1017/S0140525X08004214
Source: PubMed


Autistic-spectrum conditions and psychotic-spectrum conditions (mainly schizophrenia, bipolar disorder, and major depression) represent two major suites of disorders of human cognition, affect, and behavior that involve altered development and function of the social brain. We describe evidence that a large set of phenotypic traits exhibit diametrically opposite phenotypes in autistic-spectrum versus psychotic-spectrum conditions, with a focus on schizophrenia. This suite of traits is inter-correlated, in that autism involves a general pattern of constrained overgrowth, whereas schizophrenia involves undergrowth. These disorders also exhibit diametric patterns for traits related to social brain development, including aspects of gaze, agency, social cognition, local versus global processing, language, and behavior. Social cognition is thus underdeveloped in autistic-spectrum conditions and hyper-developed on the psychotic spectrum.;>We propose and evaluate a novel hypothesis that may help to explain these diametric phenotypes: that the development of these two sets of conditions is mediated in part by alterations of genomic imprinting. Evidence regarding the genetic, physiological, neurological, and psychological underpinnings of psychotic-spectrum conditions supports the hypothesis that the etiologies of these conditions involve biases towards increased relative effects from imprinted genes with maternal expression, which engender a general pattern of undergrowth. By contrast, autistic-spectrum conditions appear to involve increased relative bias towards effects of paternally expressed genes, which mediate overgrowth. This hypothesis provides a simple yet comprehensive theory, grounded in evolutionary biology and genetics, for understanding the causes and phenotypes of autistic-spectrum and psychotic-spectrum conditions.

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Available from: Christopher Robert Badcock, Jul 31, 2014
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    • "Both Hyper-and HypoToM can lead to errors on standard ToM tasks, but these different strategies would lead to different kinds of error (Frith, 2004). According to the diametric model of the mind and mental illness, all mental disorders can be located along this dimension of ToM ranging from Hypo-to HyperToM (Crespi & Badcock, 2008; Badcock, 2011). It has been hypothesized that individuals with ASD and individuals with psychosis spectrum disorders (PSD) may be located at the extreme ends (Ciaramidaro et al. 2015). "
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    ABSTRACT: Background: Knowledge on the risk mechanisms of psychotic experiences (PE) is still limited. The aim of this population-based study was to explore developmental markers of PE with a particular focus on the specificity of hyper-theory-of-mind (HyperToM) as correlate of PE as opposed to correlate of any mental disorder. Method: We assessed 1630 children from the Copenhagen Child Cohort 2000 regarding PE and HyperToM at the follow-up at 11-12 years. Mental disorders were diagnosed by clinical ratings based on standardized parent-, teacher- and self-reported psychopathology. Logistic regression analyses were performed to test the correlates of PE and HyperToM, and the specificity of correlates of PE v. correlates of any Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) mental disorder. Results: Univariate analyses showed the following correlates of PE: familial psychiatric liability; parental mental illness during early child development; change in family composition; low family income; regulatory problems in infancy; onset of puberty; bullying; concurrent mental disorder; and HyperToM. When estimating the adjusted effects, only low family income, concurrent mental disorder, bullying and HyperToM remained significantly associated with PE. Further analyses of the specificity of these correlates with regard to outcome revealed that HyperToM was the only variable specifically associated with PE without concurrent mental disorder. Finally, HyperToM did not share any of the investigated precursors with PE. Conclusions: HyperToM may have a specific role in the risk trajectories of PE, being specifically associated with PE in preadolescent children, independently of other family and child risk factors associated with PE and overall psychopathology at this age.
    Psychological Medicine 09/2015; DOI:10.1017/S0033291715001567 · 5.94 Impact Factor
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    • "This could also help to establish the validity of the assumption that there is a continuum of social ability relating to the number and severity of autistic traits, regardless of a clinical threshold. Social difficulties such as problems in forming or maintaining interpersonal relationships or engaging in inappropriate behaviour are often central to the everyday struggles that individuals with ASD face (Troisi 2008; Crespi and Badcock 2008). In order to design effective interventions, such as social skill training, it is important to have a detailed understanding of how individuals' symptoms may interact with the environment and disrupt everyday functioning. "
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    ABSTRACT: Measuring autistic traits in the general population has proven sensitive for examining cognition. The present study extended this to pro-social behaviour, investigating the influence of expectations to help others. A novel task describing characters in need of help was administered to students scoring high versus low on the Autism-Spectrum Quotient. Scenarios had two variants, describing either a 'clear-cut' or 'ambiguous' social rule. Participants with high versus low autistic traits were less pro-social and sympathetic overall towards the characters. The groups' ratings of char-acters' expectations were comparable, but those with high autistic traits provided more rule-based rationales in the clear-cut condition. This pattern of relatively intact knowledge in the context of reduced pro-social behaviour has implications for social skill training programmes.
    Journal of Autism and Developmental Disorders 02/2015; 45(8). DOI:10.1007/s10803-015-2393-x · 3.34 Impact Factor
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    • "—Antoine de Saint - Exupéry This parallel between psychiatric and epistemic syndromes is captured in a framework suggested by Jiro Tanaka ( 2012 ) , a student of German literature and Continental philosophy with a keen interest in the " life sciences . " Drawing on the work of Crespi and Badcock ( 2008 ) , he has pointed to a biological basis for the mutual incomprehension and hostility between Snow ' s two cultures . Along these lines , Tanaka ( 2012 , 10 ) has suggested that while " a mild psychosis lies at the heart of the humanities , or in any discipline whose primary purpose is the search for ' Meaning ' in the grand , fuzzy sense of the word , . . . "
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    ABSTRACT: Full text available at: The schism between positivism and interpretivism in the social sciences is usually explained by the explicit epistemological and methodological commitments of social scientists and philosophers. It can be better understood, though, as a collision between two contrasting cognitive modes and sensibilities, rooted in the predominant recruitment of two distinct networks in the human brain. Since the activation of these networks is negatively correlated, the analytic reasoning typical of positivists and the empathetic, intuitive, and holistic thinking employed by intepretivists produce incommensurate versions of social reality. The analytic cognitive mode is fostered and privileged in complex modern societies and in institutionalized social-science research. It is nevertheless inadequate for understanding the social world, as it facilitates the modeling of causal interactions between inanimate objects.
    Critical Review 01/2015; DOI:10.1080/08913811.2015.975915 · 0.63 Impact Factor
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