Abnormal involuntary movements are linked to psychosis-risk in children and adolescents: Results of a population-based study

A Developmental Perspective on Early and Current Motor Abnormalities and Psychotic-Like Symptoms

BACKGROUND AND HYPOTHESIS

Psychotic-like experiences (PLEs) are prevalent in the general population and, because they represent a lower end of the psychosis vulnerability spectrum, may be useful in informing mechanistic understanding. Although it is well-understood that motor signs characterize formal psychotic disorders, the developmental trajectory of these features and their relationships with PLEs are less well-understood.

STUDY DESIGN

Data from 7559 adolescents and young adults (age 11-21) in the Philadelphia Neurodevelopmental Cohort were used to investigate whether early-life milestone-attainment delays relate to current adolescent sensorimotor functioning and positive and negative PLEs. Current sensorimotor functioning was assessed using the Computerized Finger Tapping task (assessing motor slowing) and Mouse Practice task (assessing sensorimotor planning).

STUDY RESULTS

Early developmental abnormalities were related to current adolescent-aged motor slowing (t(7415.3) = -7.74, corrected-P < .001) and impaired sensorimotor planning (t(7502.5) = 5.57, corrected-P < .001). There was a significant interaction between developmental delays and current sensorimotor functioning on positive and negative PLEs (t = 1.67-4.51), such that individuals with early developmental delays had a stronger positive relationship between sensorimotor dysfunction and PLEs. Importantly, interaction models were significantly better at explaining current PLEs than those treating early and current sensorimotor dysfunction independently (χ2 = 4.89-20.34).

CONCLUSIONS

These findings suggest a relationship between early developmental delays and current sensorimotor functioning in psychosis proneness and inform an understanding of heterotypic continuity as well as a neurodevelopmental perspective of motor circuits. Furthermore, results indicate that motor signs are a clear factor in the psychosis continuum, suggesting that they may represent a core feature of psychosis vulnerability.

Aberrant brain dynamics in individuals with clinical high risk of psychosis

Background

Resting-state network (RSN) functional connectivity analyses have profoundly influenced our understanding of the pathophysiology of psychoses and their clinical high risk (CHR) states. However, conventional RSN analyses address the static nature of large-scale brain networks. In contrast, novel methodological approaches aim to assess the momentum state and temporal dynamics of brain network interactions.

Methods

Fifty CHR individuals and 33 healthy controls (HC) completed a resting-state functional MRI scan. We performed an Energy Landscape analysis, a data-driven method using the pairwise maximum entropy model, to describe large-scale brain network dynamics such as duration and frequency of, and transition between, different brain states. We compared those measures between CHR and HC, and examined the association between neuropsychological measures and neural dynamics in CHR.

Results

Our main finding is a significantly increased duration, frequency, and higher transition rates to an infrequent brain state with coactivation of the salience, limbic, default mode and somatomotor RSNs in CHR as compared to HC. Transition of brain dynamics from this brain state was significantly correlated with processing speed in CHR.

Conclusion

In CHR, temporal brain dynamics are attracted to an infrequent brain state, reflecting more frequent and longer occurrence of aberrant interactions of default mode, salience, and limbic networks. Concurrently, more frequent and longer occurrence of the brain state is associated with core cognitive dysfunctions, predictors of future onset of full-blown psychosis.

Speech characteristics yield important clues about motor function: Speech variability in individuals at clinical high-risk for psychosis

BACKGROUND AND HYPOTHESIS

Motor abnormalities are predictive of psychosis onset in individuals at clinical high risk (CHR) for psychosis and are tied to its progression. We hypothesize that these motor abnormalities also disrupt their speech production (a highly complex motor behavior) and predict CHR individuals will produce more variable speech than healthy controls, and that this variability will relate to symptom severity, motor measures, and psychosis-risk calculator risk scores.

STUDY DESIGN

We measure variability in speech production (variability in consonants, vowels, speech rate, and pausing/timing) in N = 58 CHR participants and N = 67 healthy controls. Three different tasks are used to elicit speech: diadochokinetic speech (rapidly-repeated syllables e.g., papapa…, pataka…), read speech, and spontaneously-generated speech.

STUDY RESULTS

Individuals in the CHR group produced more variable consonants and exhibited greater speech rate variability than healthy controls in two of the three speech tasks (diadochokinetic and read speech). While there were no significant correlations between speech measures and remotely-obtained motor measures, symptom severity, or conversion risk scores, these comparisons may be under-powered (in part due to challenges of remote data collection during the COVID-19 pandemic).

CONCLUSION

This study provides a thorough and theory-driven first look at how speech production is affected in this at-risk population and speaks to the promise and challenges facing this approach moving forward.

Facial and upper-limb movement abnormalities in individuals with psychotic-like experiences: a motion analysis study

Slow movements and irregular muscle contraction have been reported separately in different studies targeting individuals with psychotic-like experiences (PLEs). To date, it remains unknown whether these two movement abnormalities, possibly associated with hypo- and hyper-dopaminergia, respectively, co-existed in one sample with PLEs and interrelated in the early stage of psychotic progression. Therefore, this study was to examine if facial and upper-limb slow movements and irregular muscle contraction co-existed in individuals with PLEs, interrelated, and were associated with PLEs. A total of 26 individuals with PLEs, who were identified using the 16-item Prodromal Questionnaire, and 26 age- and gender-matched healthy controls received the facial and upper-limb movement measurement. A motion capture system was used to record the movement procedure and thus calculate kinematic variables that represented severity of slow movements and irregular muscle contraction. Results showed that facial and upper-limb slow movements and facial irregular muscle contraction existed in individuals with PLEs. For the total sample, slower facial movements were associated with less regular facial muscle contraction; slower upper-limb movements were associated with less regular upper-limb muscle contraction. Slower and less regular facial and upper-limb movements were associated with more severe PLEs. Compensatory changes in dopaminergic neural pathways in response to elevated dopamine might explain connection between slow movements and irregular muscle contraction. Because of the ability to detect facial and upper-limb movement abnormalities objectively and sensitively, motion analysis has great applicability to sensorimotor studies for people in the psychosis continuum.

Motor abnormalities are associated with poor social and functional outcomes in schizophrenia

BACKGROUND

Up to 50% of patients with schizophrenia are suffering from motor abnormalities, which may contribute to decreased quality of life, impaired work capacity, and a reduced life expectancy by 10-20 years. However, the effect of motor abnormalities on social and global functioning, as well as, functional capacity is not clear. We hypothesized, that the presence of motor abnormalities is associated with poorer functional outcomes in patients with schizophrenia.

METHODS

We collected data on 5 different motor abnormalities in 156 patients suffering from schizophrenia spectrum disorders: parkinsonism, catatonia, dyskinesia, neurological soft signs and psychomotor slowing (PS). Additionally, we used three different scales to evaluate the functional outcomes in these patients: the Global Assessment of Functioning (GAF) and the Social and Occupational Functioning Assessment Scale (SOFAS) which use clinicians' judgment; and one using a performance-based measure of functional capacity, the brief version of the UCSD Performance-based Skills Assessment (UPSA-B).

RESULTS

Our analysis demonstrated that patients with catatonia (all F > 4.5; p < 0.035) and parkinsonism (all F > 4.9; p < 0.027) scored lower on GAF and SOFAS compared to patients without catatonia and parkinsonism. In contrast, no significant difference on functional outcomes between patients with dyskinesia versus without dyskinesia exist in our study. Furthermore, there are statistically significant negative correlations for parkinsonism and PS with GAF, SOFAS and UPSA-B (all tau are at least -0.152, p-value <0.036). We also found significant negative correlations between catatonia and both GAF & SOFAS (all tau are at least -0.203, p-value<0.001) and between NES and SOFAS (tau = -0.137, p-value = 0.033).

CONCLUSION

Here, we showed that four of the most common motor abnormalities observed in schizophrenia were associated with at least one of the patients' functional outcomes. The stronger the motor impairment was the worse the global and social functioning. Future studies need to test, whether amelioration of motor abnormalities is linked to improved community functioning.

Basic symptoms and gray matter volumes of patients at clinical high risk for psychosis

BACKGROUND

Clinical high-risk (CHR) for psychosis is indicated by ultra-high risk (UHR) and basic symptom (BS) criteria; however, conversion rates are highest when both UHR and BS criteria are fulfilled (UHR&BS). While BSs are considered the most immediate expression of neurobiological aberrations underlying the development of psychosis, research on neurobiological correlates of BS is scarce.

METHODS

We investigated gray matter volumes (GMV) of 20 regions of interest (ROI) previously associated with UHR criteria in 90 patients from the Bern early detection service: clinical controls (CC), first-episode psychosis (FEP), UHR, BS and UHR&BS. We expected lowest GMV in FEP and UHR&BS, and highest volume in CC with UHR and BS in-between.

RESULTS

Significantly, lower GMV was detected in FEP and UHR&BS patients relative to CC with no other significant between-group differences. When ROIs were analyzed separately, seven showed a significant group effect (FDR corrected), with five (inferior parietal, medial orbitofrontal, lateral occipital, middle temporal, precuneus) showing significantly lower GM volume in the FEP and/or UHR&BS groups than in the CC group (Bonferroni corrected). In the CHR group, only COGDIS scores correlated negatively with cortical volumes.

CONCLUSIONS

This is the first study to demonstrate that patients who fulfill both UHR and BS criteria - a population that has been associated with higher conversion rates - exhibit more severe GMV reductions relative to those who satisfy BS or UHR criteria alone. This result was mediated by the BS in the UHR&BS group, as only the severity of BS was linked to GMV reductions.

Using Virtual Reality as a Tool in the Rehabilitation of Movement Abnormalities in Schizophrenia

Movement abnormalities are prevalent across all stages of schizophrenia contributing to poor social functioning and reduced quality of life. To date, treatments are scarce, often involving pharmacological agents, but none have been shown to improve movement abnormalities effectively. Virtual reality (VR) is a tool used to simulate virtual environments where behavioral performance can be quantified safely across different tasks while exerting control over stimulus delivery, feedback and measurement in real time. Sensory information is transmitted via a head mounted display allowing users to directly interact with virtual objects and bodies using gestures and body movements in the real world to perform different actions, permitting a sense of immersion in the simulated virtual environment. Although, VR has been widely used for successful motor rehabilitation in a variety of different neurological domains, none have been exploited for motor rehabilitation in schizophrenia. The objectives of this article are to review movement abnormalities specific to schizophrenia, and how VR can be utilized to restore and improve motor functioning in patients with schizophrenia. Constructing VR-mediated motor-cognitive interventions that can help in retaining and transferring the learned outcomes to real life are also discussed.

Early childhood social communication deficits in youth at clinical high-risk for psychosis: Associations with functioning and risk

Effective social functioning requires a broad range of social communication skills that are impaired in psychosis populations. However, little is known about early childhood (4- to 5-year period) social communication during the premorbid (pre-illness) stage of psychosis. The present study utilized retrospective parent reports to examine total early childhood social communication deficits, as well as deficits in two distinct domains, reciprocal social interaction (social smiling/eye gaze) and communication (social chat/gesture), in youth at clinical high-risk (CHR) for psychosis (ages 13-21; 37.2% female). Furthermore, associations between early childhood social communication and CHR youth's current functioning (social, academic/work), symptoms (positive/negative), and risk for conversion to psychosis were examined. Compared to healthy controls, CHR individuals had greater deficits in total and communication-specific early childhood social communication. Early childhood total, communication, and reciprocal social interaction deficits were associated with worse current functioning and greater current negative symptom severity (amotivation/anhedonia) in CHR youth. Early childhood total and reciprocal social interaction deficits were also associated with increased risk for conversion. These findings inform the field's understanding of the etiology and pathophysiology of psychosis by extending the current developmental literature on premorbid deficits in psychosis populations to specific domains of social behavior in a critical developmental period.

Deep hypothermia prevents striatal alterations produced by perinatal asphyxia: Implications for the prevention of dyskinesia and psychosis

GABAergic medium spiny neurons are the main neuronal population in the striatum. Calbindin is preferentially expressed in medium spiny neurons involved in the indirect pathway. The aim of the present work is to analyze the effect of perinatal asphyxia on different subpopulations of GABAergic neurons in the striatum and to assess the outcome of deep therapeutic hypothermia. The uterus of pregnant rats was removed by cesarean section and the fetuses were exposed to hypoxia by immersion in water (19 min) at 37°C (perinatal asphyxia). The hypothermic group was exposed to 10°C during 30 min after perinatal asphyxia. The rats were euthanized at the age of one month (adolescent/adult rats), their brains were dissected out and coronal sections were immunolabeled for calbindin, calretinin, NeuN, and reelin. Reelin+ cells showed no staining in the striatum besides subventricular zone. The perinatal asphyxia (PA) group showed a significant decrease in calbindin neurons and a paradoxical increase in neurons estimated by NeuN staining. Moreover, calretinin+ cells, a specific subpopulation of GABAergic neurons, showed an increase caused by PA. Deep hypothermia reversed most of these alterations probably by protecting calbindin neurons. Similarly, there was a reduction of the diameter of the anterior commissure produced by the asphyxia that was prevented by hypothermic treatment.

Quantifying the Core Deficit in Classical Schizophrenia

In the classical descriptions of schizophrenia, Kraepelin and Bleuler recognized disorganization and impoverishment of mental activity as fundamental symptoms. Their classical descriptions also included a tendency to persisting disability. The psychopathological processes underlying persisting disability in schizophrenia remain poorly understood. The delineation of a core deficit underlying persisting disability would be of value in predicting outcome and enhancing treatment. We tested the hypothesis that mental disorganization and impoverishment are associated with persisting impairments of cognition and role function, and together reflect a latent core deficit that is discernible in cases diagnosed by modern criteria. We used Confirmatory Factor Analysis to determine whether measures of disorganization, mental impoverishment, impaired cognition, and role functioning in 40 patients with schizophrenia represent a single latent variable. Disorganization scores were computed from the variance shared between disorganization measures from 3 commonly used symptom scales. Mental impoverishment scores were computed similarly. A single factor model exhibited a good fit, supporting the hypothesis that these measures reflect a core deficit. Persisting brain disorders are associated with a reduction in post-movement beta rebound (PMBR), the characteristic increase in electrophysiological beta amplitude that follows a motor response. Patients had significantly reduced PMBR compared with healthy controls. PMBR was negatively correlated with core deficit score. While the symptoms constituting impoverished and disorganized mental activity are dissociable in schizophrenia, nonetheless, the variance that these 2 symptom domains share with impaired cognition and role function, appears to reflect a pathophysiological process that might be described as the core deficit of classical schizophrenia.

Dyskinesia in Treatment-Naive and Stimulant-Treated Children With ADHD

Objective: Stimulants are safe and effective medications for the treatment of ADHD. There are a number of case studies that report stimulant-induced dyskinesia. The aim of this study was to compare dyskinesia in a treated and a treatment-naive group of children with ADHD, and a healthy control group. Method: Children aged 6 to 18 years were involved in the study (n = 158). Diagnosis of ADHD was measured with the Mini International Neuropsychiatric Interview Kid (MINI Kid). Dyskinesia was assessed with the Abnormal Involuntary Movement Scale (AIMS). Results: Before methylphenidate administration, the treated ADHD group showed significantly higher AIMS total score than the control group (p = .001) and the treatment-naive ADHD group (p < .001). We found the same pattern 1.5 hr after methylphenidate administration. Conclusion: These results call attention that clinicians should take special care for the possible development of dyskinesia during the treatment of their ADHD patients with methylphenidate.

Relationship between motor function and psychotic symptomatology in young-adult patients with schizophrenia

Motor abnormalities have been indicated to be a core manifestation of schizophrenia and not just motor side-effects of antipsychotics. However, little is known about whether all of the complete motor function, including fine motor function, muscle strength, and balance is linked to psychotic symptoms. Therefore, this study was to investigate association between complete motor function and psychotic symptoms in young-adult schizophrenia patients who had no extrapyramidal motor symptoms, which were assessed using the Extrapyramidal Symptom Rating Scale. Seventy schizophrenia patients were recruited. Fine motor function, muscle strength, and balance were assessed using The McCarron Assessment of Neuromuscular Development. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale. Given gender differences in muscle power, the correlation between muscle strength and psychotic symptoms was analyzed by gender separately. Partial correlation controlling for effects of the chlorpromazine equivalent dosage of antipsychotics was conducted. Better fine motor function was correlated with less-severe negative symptoms (r = - 0.49, p < 0.001) in the total sample. In men, better muscle strength was correlated with more severe positive symptoms and less-severe negative symptoms (r = 0.41, p = 0.008; r = - 0.55, p < 0.001). The link between motor function and psychotic symptoms may support the cerebellar and basal ganglia hypotheses of schizophrenia, proposing that diverse schizophrenia symptoms may share the same neural deficiency, that is, dysfunction of cerebellum or basal ganglia. Considering the moderate-to-strong association between muscle strength and psychotic symptoms, muscle strength might be a powerful physical predictor of psychotic progression.

State-Dependent Functional Dysconnectivity in Youth With Psychosis Spectrum Symptoms

Psychosis spectrum disorders are conceptualized as neurodevelopmental disorders accompanied by disruption of large-scale functional brain networks. Dynamic functional dysconnectivity has been described in patients with schizophrenia and in help-seeking individuals at clinical high risk for psychosis. Less is known, about developmental aspects of dynamic functional network connectivity (dFNC) associated with psychotic symptoms (PS) in the general population. Here, we investigate resting state functional magnetic resonance imaging data using established dFNC methods in the Philadelphia Neurodevelopmental Cohort (ages 8-22 years), including 129 participants experiencing PS and 452 participants without PS (non-PS). Functional networks were identified using group spatial independent component analysis. A sliding window approach and k-means clustering were applied to covariance matrices of all functional networks to identify recurring whole-brain connectivity states. PS-associated dysconnectivity of default mode, salience, and executive networks occurred only in a few states, whereas dysconnectivity in the sensorimotor and visual systems in PS youth was more pervasive, observed across multiple states. This study provides new evidence that disruptions of dFNC are present even at the less severe end of the psychosis continuum in youth, complementing previous work on help-seeking and clinically diagnosed cohorts that represent the more severe end of this spectrum.

Neuropsychological deficits in participants at clinical high risk for psychosis recruited from the community: relationships to functioning and clinical symptoms

BACKGROUND

The current study examined the pattern of neurocognitive impairments in a community-recruited sample of clinical high-risk (CHR) participants and established relationships with psychosocial functioning.

METHODS

CHR-participants (n = 108), participants who did not fulfil CHR-criteria (CHR-negatives) (n = 42) as well as a group of healthy controls (HCs) (n = 55) were recruited. CHR-status was assessed using the Comprehensive Assessment of At-Risk Mental States (CAARMS) and the Schizophrenia Proneness Instrument, Adult Version (SPI-A). The Brief Assessment of Cognition in Schizophrenia Battery (BACS) as well as tests for emotion recognition, working memory and attention were administered. In addition, role and social functioning as well as premorbid adjustment were assessed.

RESULTS

CHR-participants were significantly impaired on the Symbol-Coding and Token-Motor task and showed a reduction in total BACS-scores. Moreover, CHR-participants were characterised by prolonged response times (RTs) in emotion recognition as well as by reductions in both social and role functioning, GAF and premorbid adjustments compared with HCs. Neurocognitive impairments in emotion recognition accuracy, emotion recognition RT, processing speed and motor speed were associated with several aspects of functioning explaining between 4% and 12% of the variance.

CONCLUSION

The current data obtained from a community sample of CHR-participants highlight the importance of dysfunctions in motor and processing speed and emotion recognition RT. Moreover, these deficits were found to be related to global, social and role functioning, suggesting that neurocognitive impairments are an important aspect of sub-threshold psychotic experiences and a possible target for therapeutic interventions.

Functional and structural correlates of abnormal involuntary movements in psychosis risk and first episode psychosis

BACKGROUND

Abnormal involuntary movements (AIM) may occur throughout the course of psychosis. While AIM are thought to indicate striatal abnormalities, the functional and structural correlates of increased AIM remain elusive. Here, we examined the prevalence of AIM in patients with clinical high risk for psychosis (CHR), first episode psychosis (FEP) and clinical controls (CC). Furthermore, we tested the association of AIM with regional cerebral blood flow (rCBF), grey matter volume (GMV), and premorbid IQ.

METHODS

We conducted a video-based analysis of AIM in patients with CHR (n = 45), FEP (n = 10) and CC (n = 39), recruited in the Early Detection and Intervention Center, Bern. Premorbid intelligence was evaluated using the Peabody Picture Vocabulary test. Additionally, arterial spin labeling MRIs and structural MRIs were acquired in a subgroup of the sample to investigate the association of AIM with rCBF and GMV.

RESULTS

Higher total AIM scores were detected in CHR (p = 0.02) and FEP (p = 0.04) as compared to CC. When separated for different muscle groups, lips and perioral movements were significantly increased in CHR patients as compared to CC (p = 0.009). AIM scores correlated positively with rCBF in the premotor cortex, Brodmann area 6 (p < 0.05, FWE corrected). Negative correlations were found between AIM and GMV of the corresponding caudal middle frontal gyrus (p = 0.04, FWE corrected) and premorbid intelligence (p = 0.02).

CONCLUSIONS

AIM were more frequent in the psychosis spectrum than in clinical controls. Neuroimaging findings indicate an involvement of cortical motor areas in abnormal motor behavior, instead of pure basal ganglia pathology.

Psychotic conversion of individuals at ultra-high risk for psychosis: The potential roles of schizotypy and basic symptoms

AIM

To improve strategies for the early identification of individuals at a heightened risk for the development of psychosis, we investigated the relationships and interactions between 3 psychosis-proneness dimensions for the development of schizophrenia spectrum psychosis: schizotypy, basic symptoms and the ultra-high risk (UHR) criteria.

METHODS

Seventy-seven UHR individuals and 79 healthy controls were assessed for schizotypy and basic symptoms using self-report questionnaires at baseline. UHR participants were monthly assessed for conversion to psychosis over a mean period of 25.8 months.

RESULTS

Sixteen UHR participants (20.8%) converted to schizophrenia spectrum psychosis. In stepwise Cox regression, the interaction between basic symptoms and physical anhedonia was selected as a sole predictor of conversion in UHR participants, whereby the self-reported number of the 8 basic symptoms significantly increased the risk for conversion in those with pronounced physical anhedonia.

CONCLUSION

Our findings suggest that questionnaire-assessed basic symptoms, irrespective of their predictive validity, may predict a psychotic breakdown in pre-identified UHR individuals who are with genetic vulnerability to schizophrenia. Including all 3 psychosis-proneness dimensions into prediction models might help establish a more valid pathogenetic model of schizophrenia, and moreover, may provide some clues about course alteration strategies in hopes of preventing UHR individuals from converting to psychosis.

Postural Sway Abnormalities in Schizotypal Personality Disorder

Motor abnormalities are among the most robust findings in schizophrenia, and increasing evidence suggests they are a core feature of the disorder. Postural sway during balance tasks is a highly sensitive probe of sensorimotor systems including the cerebellum, basal ganglia, and motor cortices. Postural sway deficits are present in schizophrenia as well as groups at high risk for psychosis, suggesting altered postural control may be sensitive to the pathophysiological processes associated with risk and expression of schizophrenia spectrum disorders. This study examined postural sway performance in schizotypal personality disorder (SPD). Individuals with SPD have attenuated psychotic symptoms and share genetic risk with schizophrenia but are usually free from antipsychotic medication and other illness confounds, making SPD useful for assessing candidate biomarkers. We measured postural sway using force plates in 27 individuals with SPD, 27 carefully matched controls, and 27 matched patients with schizophrenia. It was predicted that postural sway in the SPD group would fall intermediate to schizophrenia and controls. In all conditions (eyes open and closed, with feet together or apart), the SPD group swayed significantly more than the controls, as measured by path length and sway area. Moreover, the magnitude of the sway deficit was comparable in the SPD and schizophrenia groups. These findings suggest that postural sway measures may represent a sensorimotor biomarker of schizophrenia spectrum disorders.

Motion energy analysis reveals altered body movement in youth at risk for psychosis

BACKGROUND

Growing evidence suggests that movement abnormalities occur prior to the onset of psychosis. Innovations in technology and software provide the opportunity for a fine-tuned and sensitive measurement of observable behavior that may be particularly useful to detecting the subtle movement aberrations present during the prodromal period.

METHODS

In the present study, 54 youth at ultrahigh risk (UHR) for psychosis and 62 healthy controls participated in structured clinical interviews to assess for an UHR syndrome. The initial 15min of the baseline clinical interview was assessed using Motion Energy Analysis (MEA) providing frame-by-frame measures of total movement, amplitude, speed, and variability of both head and body movement separately.

RESULTS

Result showed region-specific group differences such that there were no differences in head movement but significant differences in body movement. Specifically, the UHR group showed greater total body movement and speed of body movements, and lower variation in body movement compared to healthy controls. However, there were no significant associations with positive, negative or disorganized symptom domains.

CONCLUSION

This study represents an innovative perspective on gross motor function in the UHR group. Importantly, the automated approach used in this study provides a sensitive and objective measure of body movement abnormalities, potentially guiding novel assessment and prevention of symptom development in those at risk for psychosis.

Modelling the neuromotor abnormalities of psychotic illness: Putative mechanisms and systems dysfunction

Limitations in access to antipsychotic-naïve patients and in the incisiveness of studies that can be conducted on them, together with the inevitability of subsequent antipsychotic treatment, indicate an enduring role for animal models that can inform on the pathobiology of neuromotor abnormalities in schizophrenia and related psychotic illness. This review focusses particularly on genetically modified mouse models that involve genes associated with risk for schizophrenia and with mechanisms implicated in the neuromotor abnormalities evident in psychotic patients, as well as developmental models that seek to mirror the trajectory, phenomenology and putative pathophysiology of psychotic illness. Such abnormalities are inconsistent and subtle in mice mutant for some schizophrenia risk genes but more evident for others. The phenotype of dopaminergic and glutamatergic mutants indicates the involvement of these mechanisms, informs on the roles of specific receptor subtypes, and implicates the interplay of cortical and subcortical processes. Developmental models suggest a criticality in the timing of early adversity for diversity in the relative emergence of psychological symptoms vis-à-vis neuromotor abnormalities in the overall psychosis phenotype. These findings elaborate current concepts of dysfunction in a neuronal network linking the cerebral cortex, basal ganglia, thalamus and cerebellum. Both findings in model systems and clinical evidence converge in indicating that any distinction between 'psychomotor' and 'neuromotor' abnormality is artificial and arbitrary due to a unitary origin in developmentally determined systems/network dysfunction that underlies the lifetime trajectory of psychotic illness.

Systems Neuroscience of Psychosis: Mapping Schizophrenia Symptoms onto Brain Systems

Schizophrenia research has been in a deadlock for many decades. Despite important advances in clinical treatment, there are still major concerns regarding long-term psychosocial reintegration and disease management, biological heterogeneity, unsatisfactory predictors of individual course and treatment strategies, and a confusing variety of controversial theories about its etiology and pathophysiological mechanisms. In the present perspective on schizophrenia research, we first discuss a methodological pitfall in contemporary schizophrenia research inherent in the attempt to link mental phenomena with the brain: we claim that the time-honored phenomenological method of defining mental symptoms should not be contaminated with the naturalistic approach of modern neuroscience. We then describe our Systems Neuroscience of Psychosis (SyNoPsis) project, which aims to overcome this intrinsic problem of psychiatric research. Considering schizophrenia primarily as a disorder of interindividual communication, we developed a neurobiologically informed semiotics of psychotic disorders, as well as an operational clinical rating scale. The novel psychopathology allows disentangling the clinical manifestations of schizophrenia into behavioral domains matching the functions of three well-described higher-order corticobasal brain systems involved in interindividual human communication, namely, the limbic, associative, and motor loops, including their corticocortical sensorimotor connections. The results of several empirical studies support the hypothesis that the proposed three-dimensional symptom structure, segregated into the affective, the language, and the motor domain, can be specifically mapped onto structural and functional abnormalities of the respective brain systems. New pathophysiological hypotheses derived from this brain system-oriented approach have helped to develop and improve novel treatment strategies with noninvasive brain stimulation and practicable clinical parameters. In clinical practice, the novel psychopathology allows confining the communication deficits of the individual patient, shifting attention from the symptoms to the intact resources. We have studied this approach and observed important advantages for therapeutic alliances, personalized treatment, and de-escalation strategies. Future studies will further conjoin clinical definitions of psychotic symptoms with brain structures and functions, and disentangle structural and functional deficit patterns within these systems to identify neurobiologically distinct subsyndromes. Neurobiologically homogeneous patient groups may provide new momentum for treatment research. Finally, lessons learned from schizophrenia research may contribute to developing a comprehensive perspective on human experience and behavior that integrates methodologically distinct, but internally consistent, insights from humanities and neuroscience.

Motor Dysfunction as a Risk Factor for Conversion to Psychosis Independent of Medication Use in a Psychosis-Risk Cohort

The Structured Interview for Psychosis-Risk Syndromes (SIPS) contains criteria for the Attenuated Positive Symptom Syndrome (APSS), a period of subthreshold positive symptoms that predates full-blown psychosis. Motor abnormalities are often associated with these symptoms but have not been adequately studied. We assessed a diverse sample of 192 APSS participants (27.1% female; 47.9% white; mean age = 20.03 years) for motor dysfunction (SIPS G.3. score) at baseline and conversion to psychosis every 3 months for up to 2 years. Fifty-nine (30.7%) participants converted to psychosis. Baseline G.3. score was significantly higher among converters than nonconverters (mean difference = 0.66; t[95.929] = 2.579, p < 0.05). No significant differences in baseline G.3. were found between demographic groups or those with differential medication use. These results point to the use of G.3. as a potential predictor of psychosis among APSS individuals and potentially implicate the shared biological underpinnings of motor dysfunction in the APSS and full-blown psychotic illnesses.

Tardive Dyskinesia Associated with Atypical Antipsychotics: Prevalence, Mechanisms and Management Strategies

All antipsychotics, including the atypical antipsychotics (AAPs), may cause tardive dyskinesia (TD), a potentially irreversible movement disorder, the pathophysiology of which is currently unknown. The prevention and treatment of TD remain major challenges for clinicians. We conducted a PubMed search to review the prevalence and etiology of and management strategies for TD associated with AAPs. TD prevalence rates varied substantially between studies, with an estimated prevalence of around 20% in patients using AAPs. The risk of TD is lower with AAPs than with typical antipsychotics (TAPs) but remains a problem because AAPs are increasingly being prescribed. Important risk factors associated with TD include the duration of antipsychotic use, age, and ethnicity other than Caucasian. Theories about the etiology of TD include supersensitivity of the dopamine receptors and oxidative stress, but other neurotransmitters and factors are probably involved. Studies concerning the management of TD have considerable methodological limitations. Thus, recommendations for the management of TD are based on a few trials and clinical experience, and no general guidelines for the management of TD can be established. The best management strategy remains prevention. Caution is required when prescribing antipsychotics, and regular screening is needed for early detection of TD. Other strategies may include reducing the AAP dosage, switching to clozapine, or administering vesicular monoamine transporter (VMAT)-2 inhibitors. In severe cases, local injections of botulinum toxin or deep brain stimulation may be considered. More clinical trials in larger samples are needed to gather valid information on the effect of interventions targeting TD.

Distinct Associations of Motor Domains in Relatives of Schizophrenia Patients-Different Pathways to Motor Abnormalities in Schizophrenia?

INTRODUCTION

Aberrant motor function is an integral part of schizophrenia. In fact, abnormalities are frequently found in patients, in populations at risk, and in unaffected relatives. Motor abnormalities are suspected to be relevant for the clinical outcome and could probably predict the conversion from at-risk individuals to schizophrenia. Furthermore, motor function has been argued as endophenotype of the disorder. Yet, which particular motor domain may classify as a potential endophenotype is unknown. We aimed to compare schizophrenia patients, unaffected first-degree relatives and healthy controls for different motor domains. We expected impairments in all domains in patients and in some domains in relatives.

METHOD

We included 43 schizophrenia patients, 34 unaffected first-degree relatives of schizophrenia patients, and 29 healthy control subjects, matched for age, gender, and education level. We compared motor function of four motor domains between the groups. The domains comprise neurological soft signs (NSS), abnormal involuntary movements (dyskinesia), Parkinsonism, and fine motor function including simple [finger tapping (FT)] and complex fine motor function, (i.e., dexterity as measured with the coin rotation test). Furthermore, we tested the association of motor function of the four domains with working memory, frontal lobe function, and nonverbal intelligence for each group separately using within-group bivariate correlations.

RESULTS

Schizophrenia patients showed poorer motor function in all tested domains compared to healthy controls. First-degree relatives had intermediate ratings with aberrant function in two motor domains. In detail, relatives had significantly more NSS and performed poorer in the FT task than controls. In contrast, complex fine motor function was intact in relatives. Relatives did not differ from controls in dyskinesia or Parkinsonism severity.

DISCUSSION

Taken together, schizophrenia patients have motor abnormalities in all tested domains. Thus, motor abnormalities are a key element of the disorder. Likewise, first-degree relatives presented motor deficits in two domains. A clear difference between relatives and healthy controls was found for NSS and FT. Thus, NSS and FT may be potential markers of vulnerability for schizophrenia. The lack of association between genetic risk and dyskinesia or Parkinsonism suggests distinct pathobiological mechanisms in the various motor abnormalities in schizophrenia.

Increased Striatal and Reduced Prefrontal Cerebral Blood Flow in Clinical High Risk for Psychosis

Increased striatal dopaminergic activity and decreased prefrontal functioning have been reported in individuals at clinical high risk (CHR) for psychosis. Abnormal metabolic rate might affect resting-state cerebral blood flow (rCBF) in the respective regions. Here, we examined if striatal and prefrontal rCBF differ between patients with CHR, first-episode psychosis (FEP), chronic schizophrenia-spectrum disorder (SZ) and controls. Two cohorts with a total of 122 participants were included and analyzed separately: 32 patients with SZ and 31 healthy controls (HC) from the University Hospital of Psychiatry, and 59 patients from the Bern Early Recognition and Intervention Center (29 with CHR, 12 with FEP, and 18 clinical controls [CC]). Ultra-high risk criteria were assessed with the Structured Interview for Psychosis-Risk Syndromes, basic symptom criteria with the Schizophrenia Proneness Instrument. rCBF was measured with pseudo-continuous arterial spin labeling 3T-Magnetic Resonance Imaging. Striatal rCBF was significantly increased and prefrontal rCBF significantly decreased in the SZ group compared to HC group and in the CHR and FEP groups compared to CC group. Striatal rCBF correlated significantly with positive symptom scores in SZ and CHR. An inverse correlation between striatal and frontal rCBF was found in controls (HC, CC), but not in patient groups (SZ, FEP, CHR). This is the first study to demonstrate increased neuronal activity within the striatum, but reduced prefrontal activity in patients with CHR, FEP, and SZ compared to the respective controls. Our results indicate that alterations in striatal and prefrontal rCBF are reflecting metabolic abnormalities preceding the onset of frank psychosis.

Motor System Pathology in Psychosis

PURPOSE OF REVIEW

Motor abnormalities are an intrinsic feature of psychosis. Neurological soft signs, Parkinsonism, dyskinesia, and other motor phenomena are frequently observed in subjects at clinical or genetic risk for psychosis as well as first-episode patients, chronic patients. Here, we review the most recent literature on motor assessments and pathophysiology in psychosis.

RECENT FINDINGS

Instrumental measures of fine motor performance, balance, spontaneous motor activity, and gesture indicated motor abnormalities in subjects at risk and across stages of schizophrenia. Motor phenomena are associated with distinct symptom dimensions and may indicate poor outcomes. Neuroimaging studies demonstrated altered neural maturation within critical motor networks in subjects at risk. Furthermore, specific categories of motor dysfunction were associated with distinct structural and functional alterations in the motor system in schizophrenia. Motor abnormalities provide a unique window into the pathobiology of psychosis and have the potential to guide screening, staging, and outcome prediction.

Aberrant Hyperconnectivity in the Motor System at Rest Is Linked to Motor Abnormalities in Schizophrenia Spectrum Disorders

Motor abnormalities are frequently observed in schizophrenia and structural alterations of the motor system have been reported. The association of aberrant motor network function, however, has not been tested. We hypothesized that abnormal functional connectivity would be related to the degree of motor abnormalities in schizophrenia. In 90 subjects (46 patients) we obtained resting stated functional magnetic resonance imaging (fMRI) for 8 minutes 40 seconds at 3T. Participants further completed a motor battery on the scanning day. Regions of interest (ROI) were cortical motor areas, basal ganglia, thalamus and motor cerebellum. We computed ROI-to-ROI functional connectivity. Principal component analyses of motor behavioral data produced 4 factors (primary motor, catatonia and dyskinesia, coordination, and spontaneous motor activity). Motor factors were correlated with connectivity values. Schizophrenia was characterized by hyperconnectivity in 3 main areas: motor cortices to thalamus, motor cortices to cerebellum, and prefrontal cortex to the subthalamic nucleus. In patients, thalamocortical hyperconnectivity was linked to catatonia and dyskinesia, whereas aberrant connectivity between rostral anterior cingulate and caudate was linked to the primary motor factor. Likewise, connectivity between motor cortex and cerebellum correlated with spontaneous motor activity. Therefore, altered functional connectivity suggests a specific intrinsic and tonic neural abnormality in the motor system in schizophrenia. Furthermore, altered neural activity at rest was linked to motor abnormalities on the behavioral level. Thus, aberrant resting state connectivity may indicate a system out of balance, which produces characteristic behavioral alterations.

The clinical and prognostic value of motor abnormalities in psychosis, and the importance of instrumental assessment

Motor abnormalities comprise several clinical signs intrinsic to psychosis. Critically, these features are of prognostic value in individuals at-risk for psychosis, and for those in early stages of psychotic disorders. Motor abnormalities such as tremor, rigidity, and neurological soft signs often go unrecognized. Currently, advances in this area are limited by a paucity of theoretical conceptions categorizing or linking these behaviours to underlying neurobiology affected in psychosis. However, emerging technological advances have significantly improved the ability to detect and assess motor abnormalities with objective instruments in a timely and reliable manner. Further, converging evidence has laid the groundwork for theoretically and empirically derived categorization and conceptualization. This review summarizes these advances, stressing the importance of motor abnormalities for understanding vulnerability across different stages of psychosis and introducing these innovative instrumental approaches. Patients, researchers and clinicians will benefit from these new developments, as better assessment aids the development of targeted interventions to ultimately improve the care for individuals experiencing psychosis.

Movement disorders and chronic psychosis: Five new things

Purpose of review

To discuss selected peer-reviewed research articles published between 2014 and 2016 and highlight 5 clinically relevant messages related to hyperkinetic and hypokinetic movement disorders in patients with chronic psychosis.

Recent findings

A recent population-based study complemented data from clinical trials in showing increased risk of developing extrapyramidal symptoms with antipsychotic use. A community service-based longitudinal study showed that dopamine transporter imaging could help identify subgroups of patients with parkinsonism associated with antipsychotics with a progressive course, potentially manageable with l-dopa. Data from recent noteworthy clinical trials showed that a new VMAT-2 inhibitor and, for pharmacologically refractory tardive dyskinesia, deep brain stimulation of the globus pallidus internus are promising interventions. Finally, a population-based study has confirmed that hyperkinesias (encompassing chorea, dystonia, and stereotypies) may be early predictors of psychosis even in childhood and adolescence.

Summary

Movement disorders associated with new-generation antipsychotics, including widely used agents (e.g., aripiprazole), are not rare occurrences. Better monitoring is needed to assess their true effect on patients' quality of life and functioning and to prevent underascertainment.