(Developmental) Motor Signs: Reconceptualizing a Potential Transdiagnostic Marker of Psychopathological Vulnerability

The Evolution of Symbolic Thought: At the Intersection of Schizophrenia Psychopathology, Ethnoarchaeology, and Neuroscience

The human capacity for symbolic representation arises, evolutionarily and developmentally, from the exploitation of a widespread sensorimotor network, along a fundamental continuity between embodied and symbolic modes of experience. In this regard, the fine balancing between constrained sensorimotor connections (responsible for self-embodiment processing) and more untethered neural associations (responsible for abstract and symbolic processing) is context dependent and plastically neuromodulated, thus intersubjectively constructed within a specific socio-cultural milieu. Instead, in the schizophrenia spectrum this system falls off catastrophically, due to an unbalance toward too unconstrained sensorimotor connectivity, leading to a profound distortion of self/world relation with a symbolic activity detached from its embodied ground. For this very reason, however, schizophrenia psychopathology may contribute to unveil, in a distorted or magnified way, ubiquitous structural features of human symbolic activity, beneath the various, historically determined cultural systems. In this respect, a comparative approach, linking psychopathology and ethnoarchaeology, allows highlight the following invariant formal characteristics of symbolic processing: (1) Emergence of salient perceptive fragments, which stand out from the perceptual field. (2) Spreading of a multiplicity of new significances with suspension of common-sense meaning. (3) Dynamic and passive character through which meaning proliferation is experienced. This study emphasizes the importance of fine-grained psychopathology to elucidate, within a cross-disciplinary framework, the evolutionarily and developmental pathways that shape the basic structures of human symbolization.

Developmental Trajectories of Irritability across the Transition to Toddlerhood: Associations with Effortful Control and Psychopathology

Preschool-age irritability is a transdiagnostic marker of internalizing and externalizing problems. However, researchers have generally been reluctant to examine irritability within a clinically salient framework at younger ages due to some instability during the "terrible twos" period. Developmentally sensitive and dense measurements to capture intra- and inter-individual variability, as well as exploration of developmental processes that predict change, are needed. This study aimed to examine (1) the trajectories of irritability at the transition to toddlerhood (12-24 months of age) using repeated measures, (2) whether effortful control was associated with individual differences in level and growth rate of irritability, and (3) whether individual differences in the irritability trajectories were associated with later psychopathology. Families were recruited when the child was 12-18 months old (N = 333, 45.65% female). Mothers reported on their toddler's irritability at baseline and every two months until a follow-up laboratory assessment approximately one year later. Effortful control was measured at baseline. Clinical internalizing/externalizing symptoms were measured at the follow-up assessment. Hierarchical linear models revealed an increase in irritability over time, yet there was relatively little within-person variability. Effortful control was only associated with the level of irritability and not growth rate. Level of irritability was associated with internalizing, externalizing, and combined symptoms, but growth rate was not. Findings suggest intraindividual stability in irritability at the transition to toddlerhood and the possibility that screening for elevated irritability at toddler age is meaningful.

Neuromotor dysfunction as a major outcome domain of psychotic disorders: A 21-year follow-up study

BACKGROUND

The long-term stability of neuromotor domains assessed at the first episode of psychosis (FEP) and their ability for predicting a number of outcomes remains largely unknown, and this study addressed these issues.

METHODS

This was a longitudinal study of 243 participants with FEP who were assessed at baseline for background variables and parkinsonism, dyskinesia, neurological soft signs (NSS) and catatonia, and reassessed 21 years later for the same neuromotor variables, psychopathology, functioning, personal recovery, cognitive performance and medical comorbidity. Stability of neuromotor ratings was assessed using the intraclass correlations coefficient and associations between the predictors and outcomes were examined using univariate and multivariate statistics.

RESULTS

Baseline dyskinesia and NSS ratings showed excellent stability over time whereas that for parkinsonism and catatonia was relatively low. Neuromotor dysfunction at follow-up was independently predicted by a family history of schizophrenia, obstetric complications, neurodevelopmental delay, low premorbid IQ and baseline ratings of dyskinesia and NSS. Moreover, baseline dyskinesia and NSS ratings independently predicted more positive and negative symptoms, poor functioning and less personal recovery; catatonia predicted less personal recovery and more medical comorbidity. Baseline neuromotor ratings explained between 4% (for medical comorbidity) and 34% (for neuromotor dysfunction) of the variance in the outcomes. Lastly, neuromotor dysfunction at baseline highly predicted clinical staging at follow-up.

CONCLUSION

Baseline neuromotor domains show variable stability over time and relate distinctively to very long-term outcomes. Both baseline dyskinesia and NSS are trait markers of the disease process and robust predictors of the outcomes.

Disembodiment and Language in Schizophrenia: An Integrated Psychopathological and Evolutionary Perspective

Different hypotheses have flourished to explain the evolutionary paradox of schizophrenia. In this contribution, we sought to illustrate how, in the schizophrenia spectrum, the concept of embodiment may underpin the phylogenetic and developmental pathways linking sensorimotor processes, the origin of human language, and the construction of a basic sense of the self. In particular, according to an embodied model of language, we suggest that the reuse of basic sensorimotor loops for language, while enabling the development of fully symbolic thought, has pushed the human brain close to the threshold of a severe disruption of self-embodiment processes, which are at the core of schizophrenia psychopathology. We adopted an inter-disciplinary approach (psychopathology, neuroscience, developmental biology) within an evolutionary framework, to gain an integrated, multi-perspectival model on the origin of schizophrenia vulnerability. A maladaptive over-expression of evolutionary-developmental trajectories toward language at the expense of embodiment processes would have led to the evolutionary "trade-off" of a hyper-symbolic activity to the detriment of a disembodied self. Therefore, schizophrenia psychopathology might be the cost of long-term co-evolutive interactions between brain and language.