[Sleep in a performance artist: Eight days and seven nights sitting inside a metal sculpture]. / Le sommeil d'un performeur de l'extrême. Dormir huit jours et sept nuits, assis, sans bouger, enfermé dans une sculpture.

Sleep in extreme situations has been little studied. The artist Abraham Poincheval (AP) is known for his performances in confined spaces. For his show at the Perrotin Gallery in Paris, he was enclosed for 8days and 7nights in a metal sculpture of his body in a seated position, with his head facing a work by Hans Hartung at the end of a cone system placed in front of his eyes which occluded all other visual stimuli. The interior of the metal structure was not padded and there was no head support. His sleep and internal temperature were continuously recorded using polysomnography (Grael, Compumedics) and an orally swallowed temperature sensitive capsule (Bodycap) with temperature sampling every 2min. AP slept an average of 355.1min/24h, composed of light slow-wave sleep (N1: 47.1min, N2: 192.2min), deep slow-wave sleep (N3: 100.4min), and REM sleep 4,3 % (15.4min). Sleep, although mostly nocturnal, was split into periods of no more than 20min. Deep sleep was therefore remarkably resistant to the uncomfortable experimental conditions, while REM sleep was markedly impaired, lasting only a few short minutes and followed by rapid awakening. This is probably due to the head position within the sculpture which was unsupported, so REM sleep with its inherent muscle atonia led to involuntary head flexion and was impossible to sustain for long. The thermal minimum was between 5:17 a.m. and 6:35 a.m. The amplitude of the core temperature decreased by more than 30 % between the beginning and the end of the protocol. Despite the immobility induced by the confined experimental conditions, there was no desynchronization of circadian rhythms. The sleep time was surprisingly long given the conditions, and slow-wave sleep was relatively preserved with an amount typically found in normal subjects while REM sleep was markedly impaired. Slow-wave sleep is clearly preserved underlying its central role in physical and mental homeostasis. REM sleep is clearly more fragile. The reduction in REM sleep linked to position has been found in a study of sleep in the sitting position in airplanes where loss of muscle tonus in the neck fragments REM sleep. Techniques for selective REM sleep deprivation also use muscle atonia: one of the initial techniques of selective REM sleep deprivation relied on muscle atonia in REM causing a cat to fall from a small perch into water. In man, the lack of head support is clearly a source of REM fragmentation. However in the case of this study, we cannot exclude an effect of other factors, notably the meditative techniques used by the performer to maintain attention on the painting, described as a dream state punctuated by visual hallucinations. Surprisingly, despite physical isolation within the sculpture, AP's biological rhythms remained stable. However, the conditions were not those of complete isolation: noise, the presence of the public in the gallery who occasionally talked to AP through the sculpture, and variations in light during the day were all temporal cues. In addition, a heatwave during the performance raised the temperature in the room with reduced total sleep time on the hottest night. Although the phase of the circadian rhythm measured by the internal temperature did not change, the amplitude fell which is compatible with reduced physical activity. In conclusion, under physically constraining and uncomfortable sleep conditions, deep sleep is maintained while REM sleep is starkly reduced. From a homeostatic point of view, this means that over a short period of time, in a survival situation, energy recovery through deep slow-wave sleep takes priority over REM sleep.

Gender differences in psychosocial function and self-reported health status in late-diagnosed autistic adults: results from the FACE-ASD national cohort.

BACKGROUND: While adult outcome in autism spectrum disorder (ASD) is generally measured using socially valued roles, it could also be understood in terms of aspects related to health status - an approach that could inform on potential gender differences. METHODS: We investigated gender differences in two aspects of outcome related to health-status, i.e. general functioning and self-perceived health status, and co-occurring health conditions in a large multi-center sample of autistic adults. Three hundred and eighty-three participants were consecutively recruited from the FondaMental Advanced Centers of Expertise for ASD cohort (a French network of seven expert centers) between 2013 and 2020. Evaluation included a medical interview, standardized scales for autism diagnosis, clinical and functional outcomes, self-perceived health status and verbal ability. Psychosocial function was measured using the Global Assessment of Functioning scale. RESULTS: While autistic women in this study were more likely than men to have socially valued roles, female gender was associated with poorer physical and mental health (e.g. a 7-fold risk for having three or more co-occurring physical health conditions) and a poorer self-perceived health status. Psychosocial function was negatively associated with depression and impairment in social communication. Half of the sample had multiple co-occurring health conditions but more than 70% reported that their visit at the Expert Center was their first contact with mental health services. CONCLUSIONS: To improve objective and subjective aspects of health outcome, gender differences and a wide range of co-occurring health conditions should be taken into account when designing healthcare provision for autistic adults.

Neurocognitive and neurobehavioral characterization of two frequent forms of neurodevelopmental disorders: the DYRK1A and the Wiedemann-Steiner syndromes.

DYRK1A and Wiedemann-Steiner syndromes (WSS) are two genetic conditions associated with neurodevelopmental disorders (NDDs). Although their clinical phenotype has been described, their behavioral phenotype has not systematically been studied using standardized assessment tools. To characterize the latter, we conducted a retrospective study, collecting data on developmental history, autism spectrum disorder (ASD), adaptive functioning, behavioral assessments, and sensory processing of individuals with these syndromes (n = 14;21). In addition, we analyzed information collected from families (n = 20;20) using the GenIDA database, an international patient-driven data collection aiming to better characterize natural history of genetic forms of NDDs. In the retrospective study, individuals with DYRK1A syndrome showed lower adaptive behavior scores compared to those with WSS, whose scores showed greater heterogeneity. An ASD diagnosis was established for 57% (8/14) of individuals with DYRK1A syndrome and 24% (5/21) of those with WSS. Language and communication were severely impaired in individuals with DYRK1A syndrome, which was also evident from GenIDA data, whereas in WSS patients, exploration of behavioral phenotypes revealed the importance of anxiety symptomatology and ADHD signs, also flagged in GenIDA. This study, describing the behavioral and sensorial profiles of individuals with WSS and DYRK1A syndrome, highlighted some specificities important to be considered for patients' management.

Sleep and circadian rhythm characteristics in individuals from the general population during the French COVID-19 full lockdown.

The full 2-month lockdown to fight the coronavirus disease 2019 (COVID-19) pandemic in 2020 led to substantial disruption of daily life and routines. The present study aimed to comprehensively identify the lockdown's effects on sleep, daily rhythms and emotions of the French population. A survey was published online during the last week of the 2-month full lockdown and 1,627 individuals completed the online survey. The survey was self-administered and included standardised questionnaires. Sleep schedules were delayed during lockdown in more than half of the participants. New severe delayed sleep phase affected 10% of participants with sleep schedules delayed by ≥3 hr during the lockdown compared to before. A significant decrease in exposure to morning (p < 0.001) and evening natural light (p < 0.001), a significant increase in screen exposure time (with a significant screen exposure >3 hr during the evening for 45% of the participants during lockdown versus 18% before lockdown, p < 0.001), an increase in substance use for one-quarter of participants, a poorer sleep quality in 56% of participants, and less regular sleep schedules in 48% of participants were observed. We also found a poorer sleep quality in women than men during lockdown (p = 0.004). The French full lockdown had a severe impact on sleep quality, sleep-wake rhythms, and sleep behaviours. The implementation of public health strategies for the prevention and care of sleep-wake cycles during lockdown are therefore essential.

Determinants of the evolutions of behaviours, school adjustment and quality of life in autistic children in an adapted school setting: an exploratory study with the International Classification of Functioning, disability and health (ICF).

BACKGROUND: Previous studies about Quality of Life (QoL) in autistic children (ASD) have put forward the negative impact of factors such as Autism Spectrum Disorder (ASD) severity, psychiatric comorbidities and adaptive behaviour impairment. However, little is known about the relation of these factors to school adjustment, measured with the International Classification of Functions disability and health (ICF) framework (World Health Organization, 2001), and QoL evolutions. Thus, this study aimed at investigating the determinants of behaviours, school adjustment and QoL changes in 32 children in an ASD inclusion program over one academic year. METHODS: Using Bayesian methods, we studied the impact of ASD severity, psychiatric comorbidities, adaptive behaviour level and a diagnosis of Pathological Demand Avoidance (PDA) on evolutions of behaviour, school adjustment (measured with the ICF) and QoL. RESULTS: As predicted, adequate adaptive behaviour levels were associated with better progress of behaviours and school adjustment whereas psychiatric comorbidities were related to worse outcome of school adjustment. Contrary to our hypotheses, severe ASD was associated to better evolution of adjustment at school. PDA was not discriminant. We did not find any association between the studied factors and the evolution of QoL over the academic year. CONCLUSION: Our results show that the assessment of adaptive behaviour levels, psychiatric comorbidities and ASD severity level may be useful predictors to discriminate of school adjustment evolution (assessed by teachers within the ICF model) over a one-year period in autistic children. The assessment of this time course of school adjustment was sensitive to change and adapted to differentiate evolutions in an inclusive education framework. The investigation of quality of school life of autistic children as well as its determinants may therefore be relevant to improving academic adaptation. However, further research in larger groups, over longer periods and in different personalized school settings for autistic children is needed.

Is there a dysbiosis in individuals with a neurodevelopmental disorder compared to controls over the course of development? A systematic review.

Many scientific papers reported that an unbalanced gut microbiota could lead to or worsen neurodevelopmental disorders (NDD). A dysbiosis may then be observed in the course of development and mark a dysfunction within what is called the gut-brain axis. The aim of this systematic review is to investigate potential evidence of dysbiosis in children and young adults with NDD compared to controls. Using the PRISMA guidelines we systematically reviewed studies that compared the gut microbiota in NDD participants (with an age inferior to thirty) to the gut microbiota of controls, regardless of the data analysis methods used. The MEDLINE, Scopus and PsycINFO databases were searched up to September 2018. 31 studies with a total sample size of 3002 ASD (Autism Spectrum Disorder) and 84 ADHD (Attention Deficit Hyperactivity Disorder) participants were included in this systematic review. Independent data extraction and quality assessment were conducted. The quality of the studies was rated from low to high. Population characterization and experimental methods were highly heterogeneous in terms of the data available, selection of criteria, and dysbiosis measurement. A dysbiosis was reported in 28 studies in terms of either diversity, bacterial composition or metabolome dysfunction. Due to heterogeneity, a quantitative synthesis was not applicable. In this paper, we discuss the different biases to understand the complexity of microbiota and neurodevelopmental disorders to provide leads for future cohort studies looking to answer the questions raised by the trillions of microorganisms that inhabit key body niches.

Melatonin: From Pharmacokinetics to Clinical Use in Autism Spectrum Disorder.

The role of melatonin has been extensively investigated in pathophysiological conditions, including autism spectrum disorder (ASD). Reduced melatonin secretion has been reported in ASD and led to many clinical trials using immediate-release and prolonged-release oral formulations of melatonin. However, melatonin's effects in ASD and the choice of formulation type require further study. Therapeutic benefits of melatonin on sleep disorders in ASD were observed, notably on sleep latency and sleep quality. Importantly, melatonin may also have a role in improving autistic behavioral impairments. The objective of this article is to review factors influencing treatment response and possible side effects following melatonin administration. It appears that the effects of exposure to exogenous melatonin are dependent on age, sex, route and time of administration, formulation type, dose, and association with several substances (such as tobacco or contraceptive pills). In addition, no major melatonin-related adverse effect was described in typical development and ASD. In conclusion, melatonin represents currently a well-validated and tolerated treatment for sleep disorders in children and adolescents with ASD. A more thorough consideration of factors influencing melatonin pharmacokinetics could illuminate the best use of melatonin in this population. Future studies are required in ASD to explore further dose-effect relationships of melatonin on sleep problems and autistic behavioral impairments.

[Insights and recommendations on the sleep of children and adolescents]. / Décryptages et recommandations sur le sommeil des enfants et des adolescents.

Sleep disorders in children are a frequent complaint, whether in maternal and child welfare, paediatrics or child psychiatry consultations. The subject should be taken into consideration in view of the significant consequences that these disorders can have on the child and his entourage. Since organic causes have been excluded, a good knowledge of sleep physiology and rhythms will enable the early childhood professional to effectively help parents to establish habits conducive to good sleep in their child.

Five heterogeneous HbA1c trajectories from childhood to adulthood in youth with type 1 diabetes from three different continents: A group-based modeling approach.

OBJECTIVES: Only a fraction of youth meet established targets for glycemic control; many experience deteriorating control over time. We compared trajectories of hemoglobin A1c (HbA1c) among youth from three trans-continental type 1 diabetes (T1D) registries and identified clinical variables associated with the odds of following increasing vs stable trajectories. RESEARCH DESIGN AND METHODS: Analyses included longitudinal data from 15 897 individuals age 8 to 18 with T1D for at least 2 years and HbA1c measurements in at least 5 years during the observation period. Cohorts were selected from Australasian Diabetes Data Network (ADDN; Australia), German/Austrian/Luxembourgian Diabetes-Patienten-Verlaufsdokumentation initiative (DPV; Germany/Austria/Luxembourga), and the T1D Exchange Clinic Network (T1DX; US) clinic registries. Group-based trajectory modeling and multivariable logistic regression identified unique HbA1c trajectories and their predictors. RESULTS: Five heterogeneous trajectories of glycemic control in each registry were identified: low, intermediate, high stable; intermediate and high increasing. The overall HbA1c level for each trajectory group tended to be lowest in the DPV, higher in the ADDN, and highest in the T1DX. The absolute level of HbA1c and the proportion of individuals within each trajectory varied across registries: 17% to 22% of individuals followed an increasing trajectory. Compared with maintaining a stable trajectory, following an increasing trajectory was significantly associated with ethnic minority status, lower height z-score, higher BMI z-score, insulin injection therapy, and the occurrence of severe hypoglycemia; however, these factors were not consistent across the three registries. CONCLUSIONS: We report the first multinational registry-based comparison of glycemic control trajectories among youth with T1D from three continents and identify possible targets for intervention in those at risk of an increasing HbA1c trajectory.

Effects of growth hormone treatment on adult height in severely short children with X-linked hypophosphatemic rickets.

BACKGROUND: We recently showed that a 3-year growth hormone (GH) treatment improves linear growth in severely short children with X-linked hypophosphatemic rickets (XLH). It is unknown if GH therapy increases adult height in XLH patients. METHODS: We carried out a follow-up analysis of a randomized controlled open-label GH study in short prepubertal children with XLH on phosphate and active vitamin D treatment. The changes in SD scores (SDS) of height, sitting height, leg and arm length, and sitting height index (i.e., the ratio between sitting height and height) were analyzed in 11 out of 16 patients followed-up until adult height. RESULTS: At baseline, XLH patients showed disproportionately short stature with reduced standardized height (-3.2 ± 0.6), sitting height (-1.7 ± 0.6), leg (-3.7 ± 0.7) and arm (-2.5 ± 0.8) length, and markedly elevated sitting height index (3.3 ± 0.6; each p < 0.01 versus healthy children). In GH-treated patients, adult height, sitting height, leg length, and arm length exceeded baseline values by 0.7 SDS, 1.7 SDS, 0.7 SDS, and 1.2 SDS respectively, although this was only significant for sitting height. In controls, no significant changes in linear body dimensions were noted. Adult height did not statistically differ between groups (-2.4 ± 0.7 vs -3.3 ± 1.2, p = 0.082). GH did not exaggerate body disproportion. CONCLUSIONS: Growth hormone treatment did not significantly increase adult height in this group of short children with XLH, which may be at least partly due to the small number of patients included in our study.

Factors contributing to partial remission in type 1 diabetes: analysis based on the insulin dose-adjusted HbA1c in 3657 children and adolescents from Germany and Austria.

OBJECTIVE: Insulin dose-adjusted hemoglobin A1c (HbA1C, IDAA1c) correlates well with stimulated C-peptide levels, but has not yet been evaluated in a large cohort of patients with Type 1 diabetes (T1D). METHODS: We investigated prevalence of partial remission (PREM) defined by IDAA1c ≤9 in 3657 in children with new-onset T1D who were continuously followed over 6 years. We evaluated the predictors of PREM using the multicenter database from the DPV (Diabetes Patienten Verlaufsdokumentation) registry. RESULTS: PREM occurred in 71% of patients. Median duration was 9 (0-21) months. Compared to children <5 years at T1D onset, those aged 5-10 and ≥10 years had twice the chance of developing PREM (OR: 2.08, CI: 1.67-2.60; P < .001 and OR: 2.16, CI: 1.70-2.75; P < .001). Boys were more likely to develop PREM than girls (OR 1.41, CI: 1.18-1.69; P = .0002). Further predictors for PREM were: ketoacidosis, autoantibodies, and HbA1c at T1D onset. These results were confirmed by quantile regression analysis with duration of PREM as dependent variable. CONCLUSION: This research on a large cohort provides insight into epidemiologic characteristics of PREM in T1D defined by IDAA1c. As IDAA1c does not discriminate between insulin sensitivity and secretion, available data cannot resolve whether the sex-difference in PREM reflects innate higher insulin resistance in girls, or better beta-cell recovery in boys. Further research is needed to clarify the usefulness and performance of IDAA1c in clinical practice.

A familial GLI2 deletion (2q14.2) not associated with the holoprosencephaly syndrome phenotype.

Molecular alterations of the GLI2 gene in 2q14.2 are associated with features from the holoprosencephaly spectrum. However, the phenotype is extremely variable, ranging from unaffected mutation heterozygotes to isolated or combined pituitary hormone deficiency, and to patients with a phenotype that overlaps with holoprosencephaly, including abnormal pituitary gland formation/function, craniofacial dysmorphisms, branchial arch anomalies, and polydactyly. Although many point mutations within the GLI2 gene have been identified, large (sub) microscopic deletions affecting 2q14.2 are rare. We report on a family with a 4.3 Mb deletion in 2q14 affecting GLI2 without any dysmorphologic features belonging to the holoprosencephaly spectrum. This family confirms the incomplete penetrance of genomic disturbances affecting the GLI2 gene. However, the family presented here is unique as none of the three identified individuals with a GLI2 deletion showed any typical signs of holoprosencephaly, whereas all patients reported so far were referred for genetic testing because at least one member exhibited holoprosencephaly and related features.

Circadian disorders of sleep in adolescence: impact of the multimedia.

The teenage years are a period of particular vulnerability to the desynchronization of the biological clock. Beyond geneticfactors, puberty is associated with a significant delay in the circadian phase of sleep, responsible for increasing dificulties with sleep onset at night and thus with awakening in the morning. The prevalence of Delayed Sleep Phase Syndrome (DSPS) is high in the adolescent population, affecting up to 16 % of teenagers. As sleep needs remain remarkably stable, adolescent sleep phase delay causes chronic sleep depriva- tion and subsequently daytime fatigue or even excessive daytime sleepiness, and also metabolic disturbances, neurocognitive problems associated with decreased school perfor- mance, as well as mood disorders. Whereas genetic and biological factors have been investigated by a number of studies, research on social, cognitive-behavioural or psychological factors is still limited to date. Among the latte; the technological revolution of the past decades, most importantly exposure to screens- has significantly modied adolescent behavior. This article discusses the latest research on the complex interaction of these different factors. It focusses particularly on the impact of media use on circadian disorders of sleep in adolescence.

Serotonin transporter polymorphism is associated with increased apnea-hypopnea index in older adults.

RATIONALE: A functional polymorphism of the serotonin transporter gene (5-HTTLPR) has previously been related to upper airway pathology, but its contribution to obstructive sleep apnea (OSA), a highly prevalent sleep disorder in older adults, remains unclear. OBJECTIVES: We aimed to investigate the relationship between apnea-hypopnea index (AHI) and genetic variations in the promoter region of the 5-HTTLPR in older adults. METHODS: DNA samples from 94 community-dwelling older adults (57% female, mean age 72 ± 8) were genotyped for the 5-HTTLPR polymorphism. All participants were assessed in their homes with full ambulatory polysomnography in order to determine AHI and related parameters such as hypoxia, sleep fragmentation, and self-reported daytime sleepiness. RESULTS: The 5-HTT l allele was significantly associated with AHI (p = 0.019), with l allele carriers displaying a higher AHI than s allele homozygotes. A single allele change in 5-HTTLPR genotype from s to l resulted in an increase of AHI by 4.46 per hour of sleep (95% CI, 0.75-8.17). The l allele was also associated with increased time during sleep spent at oxygen saturation levels below 90% (p = 0.014). CONCLUSIONS: The observed significant association between the 5-HTTLPR l allele and severity of OSA in older adults suggests that the l allele may be important to consider when assessing for OSA in this age group. This association may also explain some of the observed variability among serotonergic pharmacological treatment studies for OSA, and 5-HTT genotype status may have to be taken into account in future therapeutic trials involving serotonergic agents.

EMDR-Teens-cPTSD: Efficacy of Eye Movement Desensitization and Reprocessing in Adolescents with Complex PTSD Secondary to Childhood Abuse: A Case Series.

Background: Mental healthcare for children and adolescents with a history of childhood abuse constitutes a major public health issue. Indeed, abuse exposes children to severe and complex post-traumatic stress disorder (cPTSD) but also to neurodevelopmental and psychological repercussions impacting the developmental trajectory. Trauma-focused care is essential to avoid the chronicization of symptoms and disorders. Objective: The aim of this prospective case series study was to investigate the efficacy of eye movement desensitization and reprocessing (EMDR) on complex post-traumatic symptoms and associated psychiatric disorders in adolescents with a history of abuse. Method: Twenty-two adolescents, aged 12 to 17, who had been abused during childhood were included. All adolescents met ICD-11 criteria for complex PTSD. Subjective measures of PTSD and associated psychiatric disorders were taken before (T0) and after 3 months of EMDR therapy (T1). Results: The average PTSD symptom score on the CPTS-RI significantly decreased from 40.2 to 34.4 after EMDR, indicating improvement in post-traumatic symptoms. A significant decrease in the average depression score (CDI from 18.2 at T0 to 10.6 at T1), anxiety score (R-CMAS from 21.3 at T0 to 13.3 at T1), emotional regulation score (ALS from 29 at T0 to 10.8 at T1), insomnia score (ISI from 18.5 at T0 to T1 of 9.2 at T1), and harmful use of alcohol and drugs score (ADOSPA from 2.3 at T0 to 0.3 at T1) was observed after EMDR therapy, as well as an increase in quality of life (CBCL 4-16 score from 57.9 at T0 to 77.4 at T1). Conclusions: The results of this study are encouraging and suggest that EMDR may be effective in the symptom management reducing post-traumatic symptoms and certain comorbid disorders frequently seen in adolescents who have experienced childhood abuse. Further research is needed on adolescent populations suffering from cPTSD (e.g., randomized controlled trials with control groups and other therapies or evaluating the action of the different phases of the study).

Sleep and circadian rhythms in adolescents with attempted suicide.

Sleep and circadian rhythm disorders are very common in adolescents and have been linked to suicidal ideation. However, little is known about adolescent sleep before a suicide attempt (SA). The objectives of this study were to compare the sleep of adolescents aged 13 to 18 over a period of 4 weeks before a SA compared to a non-SA group, then to analyze the association between sleep, support social and well-being based on information from validated questionnaires. In 2015, 250 adolescents were included, 55 were recruited the day after a SA in French hospitals (before SA evaluations were retrospective). Logistic regression analyzes showed that during school days, bedtime was equivalent in both groups, but sleep onset latency was significantly longer in SA (86 min vs. 52 min, p = 0.016), and wake-up time was earlier (6 h 22 vs. 6 h 47, p = 0.002), resulting in a shorter total sleep time of 44 min (OR = 0.76, CI 95% [0.61-0.93]) the month preceding SA. Adolescents with longer sleep time performed better on perceived psychological well-being (p = 0.005), relationship with parents (p = 0.011) and school environment (p < 0.001). Results indicate a significant change in the quantity and quality of adolescents' subjective sleep in the 4 weeks preceding SA requiring objective measures to study the predictive properties of sleep in SA.

Investigating the borders of autism spectrum disorder: lessons from the former diagnosis of pervasive developmental disorder not otherwise specified.

Introduction: Autism Spectrum Disorder (ASD) diagnosis is relatively consensual in typical forms. The margins of the spectrum and their degree of extension, however, are controversial. This has far-reaching implications, which extend beyond theoretical considerations: first, peripheral forms of autism are more prevalent than central forms; second, we do not know how relevant typical-targeted recommendations are for atypical forms. In DSM-IV-TR, these margins of autism were studied within the category of Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS). In spite of its low reliability, this former diagnosis was of particular interest to shed light on the gray area of margins. The aim of this systematic is therefore to investigate the clinical characteristics of PDD-NOS in comparison with Autistic Disorder. Method: A stepwise systematic PRISMA literature review was conducted by searching PubMed and Web Of Science databases to select corresponding studies. Results: The systematic review included 81 studies comprising 6,644 children with PDD-NOS. Cross-sectional and longitudinal studies comparing PDD-NOS and AD showed that PDD-NOS corresponds to milder form of autism with less impact and less associated disorder, with the exception of schizophrenia and mood disorder. Discussion: Our review challenges initial views of PDD-NOS, and shows the clinical relevance of this diagnosis when dealing with the margins of autism, and the de facto diversity included in the spectrum. However, in view of the many limitations of PDD-NOS (low reliability, instability through time, low acceptability), we suggest taxonomic changes in DSM-5: we introduce a new category based on three main dimensions related to socialization impairment, emotional lability and psychotic symptoms. Conclusion: Our review argues for a distinction between AD and PDD-NOS on clinical characteristics and thus highlights the need to study the margins of autism. While the limitations of the PDD-NOS category made it irrelevant to investigate these margins from a research perspective, we believe that a multidimensional approach for mental health professionals taping socialization, emotion lability and psychotic symptoms would be interesting. Our review therefore encourage future studies to test relevant criteria for a new category and possibly identify developmental trajectories, specific interventions and treatments.