Showing papers by "Marie-Odile Krebs published in 2019"

Perinatal Exposure to Environmental Endocrine Disruptors in the Emergence of Neurodevelopmental Psychiatric Diseases: A Systematic Review

Abstract: Background: Exposure to endocrine disruptors is on the rise, with new compounds regularly incriminated. In animals and humans, this exposure during critical developmental windows has been associated with various developmental abnormalities, including the emergence of psychiatric disorders. We aimed to review the association between perinatal endocrine disruptor exposure and neurodevelopmental disorders in humans, focusing on cognitive and psychiatric disorders. Methods: We performed a systematic review with key words referring to the fields of neurodevelopment and endocrine disruptors. We reviewed 896 titles, choosing studies on the basis of titles and abstracts. We searched through the methodology sections to find perinatal exposure and neurodevelopmental disorders, following the categories indicated in the Diagnostic and Statistic Manual of Mental Disorders (5th edition). References in some studies brought us to a total of 47 studies included here. Results: Convergent studies report an association between exposure to endocrine disruptors and autism spectrum disorder, attention-deficit hyperactivity disorder, global developmental delay, intellectual disability, communication disorders and unspecified neurodevelopmental disorders. Conclusion: Sufficient data exist to report that exposure to some endocrine disruptors is a risk factor for the emergence of neurodevelopmental disorders. Studying endocrine disruptor exposure in humans is still associated with some limits that are difficult to overcome.

Longitudinal Analyses of Blood Transcriptome During Conversion to Psychosis

Abstract: The biological processes associated with the onset of schizophrenia remain largely unknown. Current hypotheses favor gene × environment interactions as supported by our recent report about DNA methylation changes during the onset of psychosis. Here, we conducted the first longitudinal transcriptomic analysis of blood samples from 31 at-risk individuals who later converted to psychosis and 63 at-risk individuals who did not. Individuals were followed for a maximum of 1 year. Blood samples were collected at baseline and at the end of follow-up and individuals served as their own controls. Differentially expressed genes between the 2 groups were identified using the RNA sequencing of an initial discovery subgroup (n = 15 individuals). The most promising results were replicated using high-throughput real-time qPCR in the whole cohort (n = 94 individuals). We identified longitudinal changes in 4 brain-expressed genes based on RNAseq analysis. One of these genes (CPT1A) was replicated in the whole cohort. The previously observed hypermethylation in NRP1 and GSTM5 during the onset of psychosis correlated with a decrease in corresponding gene expression. RNA sequencing also identified 2 co-expression networks that were impaired after conversion compared with baseline-the Wnt pathway including AKT1, CPT1A and semaphorins, and the Toll-like receptor pathway, related to innate immunity. This longitudinal study of transcriptomic changes in individuals with at-risk mental state revealed alterations during conversion to psychosis in pathways and genes relevant to schizophrenia. These results may be a first step toward better understanding psychosis onset. They may also help to identify new biomarkers and targets for disease-modifying therapeutic strategies.

Impaired attentional modulation of sensorimotor control and cortical excitability in schizophrenia.

Abstract: Impairments in attentional, working memory and sensorimotor processing have been consistently reported in schizophrenia. However, the interaction between cognitive and sensorimotor impairments and the underlying neural mechanisms remains largely uncharted. We hypothesized that altered attentional processing in patients with schizophrenia, probed through saccadic inhibition, would partly explain impaired sensorimotor control and would be reflected as altered task-dependent modulation of cortical excitability and inhibition. Twenty-five stabilized patients with schizophrenia, 17 unaffected siblings and 25 healthy control subjects were recruited. Subjects performed visuomotor grip force-tracking alone (single-task condition) and with increased cognitive load (dual-task condition). In the dual-task condition, two types of trials were randomly presented: trials with visual distractors (requiring inhibition of saccades) or trials with addition of numbers (requiring saccades and addition). Both dual-task trial types required divided visual attention to the force-tracking target and to the distractor or number. Gaze was measured during force-tracking tasks, and task-dependent modulation of cortical excitability and inhibition were assessed using transcranial magnetic stimulation. In the single-task, patients with schizophrenia showed increased force-tracking error. In dual-task distraction trials, force-tracking error increased further in patients, but not in the other two groups. Patients inhibited fewer saccades to distractors, and the capacity to inhibit saccades explained group differences in force-tracking performance. Cortical excitability at rest was not different between groups and increased for all groups during single-task force-tracking, although, to a greater extent in patients (80%) compared to controls (40%). Compared to single-task force-tracking, the dual-task increased cortical excitability in control subjects, whereas patients showed decreased excitability. Again, the group differences in cortical excitability were no longer significant when failure to inhibit saccades was included as a covariate. Cortical inhibition was reduced in patients in all conditions, and only healthy controls increased inhibition in the dual-task. Siblings had similar force-tracking and gaze performance as controls but showed altered task-related modulation of cortical excitability and inhibition in dual-task conditions. In patients, neuropsychological scores of attention correlated with visuomotor performance and with task-dependant modulation of cortical excitability. Disorganization symptoms were greatest in patients with weakest task-dependent modulation of cortical excitability. This study provides insights into neurobiological mechanisms of impaired sensorimotor control in schizophrenia showing that deficient divided visual attention contributes to impaired visuomotor performance and is reflected in impaired modulation of cortical excitability and inhibition. In siblings, altered modulation of cortical excitability and inhibition is consistent with a genetic risk for cortical abnormality.

Individual factors influencing the duration of untreated psychosis.

Abstract: Aim Duration of untreated psychosis (DUP), or the time between onset of psychosis and treatment initiation, is a prognostic factor of schizophrenia. However, few studies evaluated the relative influence of individual-related factors on this duration. The objective of this study was to evaluate the influence of socio-demographic, clinical and cannabis use on DUP. Methods This study was part of a large prospective study in help-seeking individuals referred to our specialized early detection / intervention clinic in the Service Hospitalo-Universitaire of Sainte-Anne Hospital in Paris (ICAAR study). We explored 33 consecutive patients who crossed the CAARMS' threshold of psychosis. The DUP and cannabis consumption history were explored during the baseline comprehensive assessment using all available sources (direct interviews of patients, parents, practitioners). Correlations between socio-demographic, clinical and cannabis use, and DUP were studied. A multiple linear regression model was used to determine the variables that could significantly predict DUP. Results When considered individually, none of the socio-demographic and disease characteristic factors was associated with DUP, with the exception of level of education. In the multivariate analysis, age at inclusion, negative symptoms and history of cannabis use significantly influenced DUP. Conclusion The determinants of DUP are multi-factorial and include individual centred factors, such as age, cannabis and negative symptoms. The identification of factors resulting in delayed access to care may promote the development of effective strategies to reduce DUP in early psychosis and target effective early intervention.

Can the Positive and Negative Syndrome scale (PANSS) differentiate treatment-resistant from non-treatment-resistant schizophrenia? A factor analytic investigation based on data from the Pattern cohort study.

Abstract: Treatment-Resistant Schizophrenia (TRS) and Non-Treatment-Resistant Schizophrenia (NTRS) may represent different subtypes of schizophrenia. However, few studies have investigated their PANSS symptom dimensions by Exploratory (EFA) or Confirmatory (CFA). Data from the present study are derived from 1429 patients of the Pattern study. TRS was defined by the use of clozapine in the previous year whereas NTRS by the use of non-clozapine antipsychotics ("by proxy"). Factors were chosen based on the Kaiser criterion and considered valid when loadings were greater than or equal to 0.5. The fit to the data was evaluated by CFA in comparison with well-established PANSS models, using fit indexes. The EFA yielded similar five-factor model in both groups: Negative, Positive, Anxiety/Depression, Cognitive and Excited. CFA showed a satisfactory, but not perfect, fit to the data, as compared with the previous PANSS factor analytic models. Despite the limitations regarding the 'by proxy' definition of TRS, the results of the present study show that there are no differences in the factorial structure of PANSS in patients with TRS and NTRS.

Predictive Modulation of Corticospinal Excitability and Implicit Encoding of Movement Probability in Schizophrenia.

Abstract: The ability to infer from uncertain information is impaired in schizophrenia and is associated with hallucinations and false beliefs. The accumulation of information is a key process for generating a predictive internal model, which statistically estimates an outcome from a specific situation. This study examines if updating the predictive model by the accumulation of information in absence of feedback is impaired in schizophrenia. We explored the implicit adaptation to the probability of being instructed to perform a movement (33%-Go, 50%-Go, or 66%-Go) in a Go/NoGo task in terms of reaction times (RTs), electromyographic activity, and corticospinal excitability (CSE) of primary motor cortex (M1). CSE was assessed at two time points to evaluate prediction of the upcoming instruction based on previously accumulated information: at rest (preceding the warning signal) and at the Go/NoGo signal onset. Three groups were compared: patients with schizophrenia (n = 20), unaffected siblings (n = 16), and healthy controls (n = 20). Controls and siblings showed earlier movement onset and increased CSE with higher Go probability. CSE adaptation seemed long-lasting, because the two CSE measures, at least 1500 ms apart, strongly correlated. Patients with schizophrenia failed to show movement onset (RT) adaptation and modulation of CSE. In contrast, all groups decreased movement duration with increasing Go probability. Modulation of CSE in the anticipatory phase of the potential movement reflected the estimation of upcoming response probability in unaffected controls and siblings. Impaired modulation of CSE supports the hypothesis that implicit adaptation to probabilistic context is altered in schizophrenia.

Correlation of health-related quality of life in clinically stable outpatients with schizophrenia

Abstract: Background Generic health-related quality of life (HRQoL) scales are increasingly being used to assess the effects of new treatments in schizophrenia. The objective of this study is to better understand the usefulness of generic and condition specific HRQoL scales in schizophrenia by analyzing their correlates. Methods Data formed part of the Pattern study, an international observational study among 1379 outpatients with schizophrenia. Patients were evaluated with the Mini International Neuropsychiatric Inventory, the Clinical Global Impression-Schizophrenia (CGI-SCH) Scale and the Positive and Negative Syndrome Scale (PANSS) and reported their HRQoL using the Schizophrenia Quality of Life Scale (SQLS), the Short Form-36 (SF-36), and the EuroQol-5 Dimension (EQ-5D). The two summary values of the SF-36 (the Mental Component Score and the Physical Component Score, SF-36 MCS and SF-36 PCS) were calculated. Results Higher PANSS positive dimension ratings were associated with worse HRQoL for the SQLS, EQ-5D VAS, SF-36 MCS, and SF-36 PCS. Higher PANSS negative dimension ratings were associated with worse HRQoL for the EQ-5D VAS, SF-36 MCS, and SF-36 PCS, but not for the SQLS or the EQ-5D tariff. PANSS depression ratings were associated with lower HRQoL in all the scales. There was a high correlation between the HRQoL scales. However, in patients with more severe cognitive/disorganized PANSS symptoms, the SQLS score was relatively higher than the EQ-5D tariff and SF-36 PCS scores. Conclusion This study has shown substantial agreement between three HRQoL scales, being either generic or condition specific. This supports the use of generic HRQoL measures in schizophrenia. Clinicaltrialsgov identifier NCT01634542 (July 6, 2012, retrospectively registered).

Eye Movements in Psychiatry

Abstract: In the last half century, a large body of research literature has concentrated on oculomotor function in psychiatric syndromes and especially schizophrenia spectrum disorders. The emerging picture from these studies is that specific deficits measured in specific oculomotor function tasks such as smooth eye pursuit, antisaccades and memory saccades are evident in patients with psychosis and probably to a lesser degree in their first degree relatives. Such oculomotor function deficits have helped develop a better understanding of the genetic and neurobiological substrate of psychiatric syndromes, bearing in mind that these functions have a complex genetic and neurobiological substrate that remains to be fully understood. Some of these functions such as visually guided and predictive saccades are sensitive to medication status and the natural course of psychiatric syndromes. This fact could potentially lead to the future development of oculomotor biological markers for treatment response and outcome predictions in these syndromes.

Paris MEM: a study protocol for an effectiveness and efficiency trial on the treatment of traumatic stress in France after the 2015–16 terrorist attacks

Abstract: The Paris and Nice terrorist attacks affected a thousand of trauma victims and first-line responders. Because there were concerns that this might represent the first of several attacks, there was a need to quickly enhance the local capacities to treat a large number of individuals suffering from trauma-related disorders. Since Reconsolidation Therapy (RT) is brief, relatively easy to learn, well tolerated and effective, it appeared as the ideal first-line treatment to teach to clinicians in this context. This study protocol is a two-arm non-randomized, multicenter controlled trial, comparing RT to treatment as usual for the treatment of trauma-related disorders. RT consists of actively recalling one’s traumatic event under the influence of the s-blocker propranolol, once a week, for 10–25 min with a therapist, over 6 consecutive weeks. This protocol evaluates the feasibility, effectiveness, and cost-utility of implementing RT as part of a large multi-center (N = 400) pragmatic trial with a one-year follow-up. Paris MEM is the largest trial to date assessing the efficiency of RT in the aftermath of a large-scale man-made disaster. RT could possibly reinforce the therapeutic arsenal for the treatment of patients suffering from trauma-related disorders, not only for communities in western countries but also worldwide for terror- or disaster-stricken communities. Clinical Trials (ClinicalTrials.gov). June 3, 2016. NCT02789982.

Non-cell autonomous OTX2 transcription factor regulates anxiety-related behaviors in the mouse

Abstract: The Otx2 homeoprotein transcription factor is expressed in the dopaminergic neurons of the ventral tegmental area, a mesencephalic nucleus involved in the control of complex behaviors through its projections to limbic structures, including the ventral hippocampus, amygdala, nucleus accumbens and prefrontal cortex. We find adult mice heterozygous for Otx2 show a hypoanxious phenotype in light-dark box and elevated plus maze paradigms. However, the number of dopaminergic neurons, the integrity of their axons, their projection patterns in target structures, and the amounts of dopamine and dopamine metabolites in targets structures were not modified in the Otx2 mutant. Because OTX2 is expressed by the choroid plexus, secreted into cerebrospinal fluid and transferred to parvalbumin interneurons of the cortex, hippocampus, and amygdala, we investigated if the hypoanxiety of Otx2 heterozygous mice could result from the decreased synthesis of Otx2 in the choroid plexus. Indeed, hypoanxious phenotype was reversed by the overexpression of Otx2 specifically in choroid plexus of adult Otx2 heterozygous mice, while hypoanxious phenotype could be induced in adult wild type mice by lowering OTX2 levels in the cerebrospinal fluid. Taken together, OTX2 synthesis by the choroid plexus followed by its secretion into the cerebrospinal fluid is an important regulator of the anxiety phenotype in the mouse.