Childhood schizotypal features vs. high-functioning autism spectrum disorder: Developmental overlaps and phenomenological differences

Multiple complex developmental disorder (MCDD): Did we throw the baby out with the bathwater too fast? A systematic review

BACKGROUND

Multiple complex developmental disorder (MCDD) manifests as early-onset impairment across different domains. Although it could appear as a transitional condition between autism and childhood-onset schizophrenia, interest in MCDD has progressively waned. This study attempts to discern MCDD current relevance to avoid "throwing the baby out with the bathwater" too fast.

METHODS

All available studies published up to January 2024 were retrieved and evaluated following on the PRISMA guidelines for systematic reviews using the term "multiple complex developmental disorder" or "MCDD", without any filter for study design nor year of publication.

RESULTS

Only 16 studies were included and analyzed. Overall, a variable heterogeneity was observed in terms of country of investigation, study design, and clinical groups. Most of the included studies explored the construct of MCDD in developmental age, comparing MCDD mostly with autistic patients, and observing how the former group had higher levels of paranoia, illusions, and psychotic thoughts, whereas the latter showed more frequently difficulties in social interactions and stereotypical behaviors.

CONCLUSION

Overall, these results showed how progressive changes in diagnostic criteria over time led MCDD to be abandoned as nosographic construct, leaving perhaps a diagnostic void between autism and psychotic disorders that needs to be further studied. A systematic review on the Multiple Complex Developmental Disorder (MCDD): a forgotten diagnosis between autism and schizophrenia.

Schizophrenia spectrum disorders in children and adolescents: Clinical, phenomenological, diagnostic, and prognostic features across subtypes

Schizophrenia spectrum disorders (SSD) typically have a diagnostically recognizable onset in young adulthood, yet it is not unusual that help-seeking due to initial SSD-related clinical manifestations emerge in earlier developmental phases, such as childhood and adolescence. Varieties of SSD manifestations in children and adolescents can be distinguished according to variations in clinical expressivity, severity and timing (i.e. developmental stage). Some individuals may reach the full clinical threshold for a diagnosis of schizophrenia according to the same descriptive diagnostic criteria used for adults, and in this case, it's possible to distinguish a pre-pubertal onset in childhood (aka Very Early Onset Schizophrenia, VEOS) and a post-pubertal onset in adolescence (aka Early Onset Schizophrenia, EOS). Other individuals may not reach such clinically overt diagnostic threshold but nonetheless present Childhood Schizotypal Disorder (CSD) or a Clinical High-Risk for Psychosis (CHRP). While EOS is clinically more similar to the canonical adult-onset presentation, the other 3 subgroups (i.e. VEOS, CSD, CHRP) present more nuances and specific clinical characteristics, which require ad-hoc developmental and phenomenological considerations for appropriate differential diagnosis and prognosis. Therefore, current scoping review intends to saturate such knowledge gap with respect to early SSD-phenotypes.

Autism Spectrum Disorder and Early Psychosis: a narrative review from a neurodevelopmental perspective

Autism Spectrum Disorder (ASD), characterized by socio-communicative abnormalities and restricted, repetitive, and stereotyped behaviors, is part of Neurodevelopmental Disorders (NDDs), a diagnostic category distinctly in accordance with the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, (DSM-5), clearly separated from Schizophrenia Spectrum Disorder (SSD) (schizophrenia, schizophreniform disorder, schizoaffective disorder, schizotypal personality disorder). Over the last four decades, this clear distinction is gradually being replaced, describing ASD and SSD as two heterogeneous conditions but with neurodevelopmental origins and overlaps. Referring to the proposal of a neurodevelopmental continuum model, the current research's aim is to provide an update of the knowledge to date on the course of clinical symptoms and their overlaps among ASD and SSD. A narrative review of the literature published between January 2010 and June 2023 was conducted. Five studies were included. All studies show a global impairment in both conditions. Two studies show a focus on neurodevelopmental perspective in ASD and SSD. Only one study of these adopts a longitudinal prospective in terms of prognostic markers among ASD and SSD. Three studies underline the overlap between ASD and SSD in terms of negative, disorganized and positive symptomatology. To date, there is a gap in the current scientific literature focused on ASD-SSD course of clinical symptoms and their overlaps from a neurodevelopmental perspective. Future longitudinal studies to identify risk markers and tailored treatments are needed.

Attenuated niacin skin flushing response in children and adolescents with mental disorders: A transdiagnostic early warning marker

Mental disorders are the leading cause of disability in children and adolescents worldwide, but among the difficulties that pediatric mental health faces is a lack of objective biomarkers used for early identification or diagnosis. Studies to date indicate that niacin skin flushing response (NSFR) could be a biomarker for adult patients with schizophrenia and affective disorders. However, there are limited data on NSFR in pediatric patients with mental disorders. This study provides the first evidence of NSFR as a potential transdiagnostic marker in pediatric patients with schizophrenia (SZ), bipolar disorder (BD), depressive disorder (DD) and autism spectrum disorder (ASD). We conducted 10-min niacin skin flush tests on 227 pediatric participants, including 59 SZ patients, 23 BD patients, 57 DD patients, 40 ASD patients and 48 healthy controls (HCs). Group, time and the concentrations of aqueous methyl nicotinate had significant effects on the flush scores. Pediatric patients with BD, DD, and SZ clustered together, while ASD patients appeared to be more similar with HCs. SZ, BD and DD groups had lower flush scores than HCs, while ASD group had higher scores than BD and DD groups. These findings suggested NSFR was blunted in pediatric SZ, BD and DD and was distinct in ASD from the other disease groups. Our data demonstrate NSFR could be a transdiagnostic marker for pediatric SZ, BD and DD, which would help to identify a subgroup of patients sharing dysfunctions of membrane phospholipids. Besides, NSFR might have potential for early identification of affective disorders from ASD.

The Relationship Between Affective Visual Mismatch Negativity and Interpersonal Difficulties Across Autism and Schizotypal Traits

Sensory deficits are a feature of autism and schizophrenia, as well as the upper end of their non-clinical spectra. The mismatch negativity (MMN), an index of pre-attentive auditory processing, is particularly sensitive in detecting such deficits; however, little is known about the relationship between the visual MMN (vMMN) to facial emotions and autism and schizophrenia spectrum symptom domains. We probed the vMMN to happy, sad, and neutral faces in 61 healthy adults (18-40 years, 32 female), and evaluated their degree of autism and schizophrenia spectrum traits using the Autism Spectrum Quotient (AQ) and Schizotypal Personality Questionnaire (SPQ). The vMMN to happy faces was significantly larger than the vMMNs to sad and neutral faces. The vMMN to happy faces was associated with interpersonal difficulties as indexed by AQ Communication and Attention to Detail subscales, and SPQ associated with more interpersonal difficulties. These data suggest that pre-attentive processing of positive affect might be more specific to the interpersonal features associated with autism and schizophrenia. These findings add valuable insights into the growing body of literature investigating symptom-specific neurobiological markers of autism and schizophrenia spectrum conditions.

Treatment Approaches for First Episode and Early-Phase Schizophrenia in Adolescents and Young Adults: A Delphi Consensus Report from Europe

PURPOSE

Although first-episode psychosis (FEP) in youth, particularly early-onset schizophrenia (EOS), is managed similarly to adult-onset schizophrenia, few antipsychotics are approved for people aged 13-18 years. We aimed to explore areas of uncertainty in EOS management and provide evidence-based recommendations to mental health specialists. We used the Delphi methodology to gain knowledge in areas lacking evidence-based strategies. This standardized methodology consists of the development of a questionnaire by content experts, which is then submitted to a broader panel of professionals (panelists) to survey their level of agreement on the topics proposed.

MATERIALS AND METHODS

The developed questionnaire covered patient management from diagnosis to maintenance treatment and was administered to a broader panel of specialists across Europe. Based on an analysis of responses received in this first round, the items that needed further insight were submitted to the panel for a second round and then reanalysed.

RESULTS

An initial set of 90 items was developed; in round I, consensus was reached for 83/90 items (92%), while it was reached for 7/11 (64%) of the items sent out for rerating in round II. Feedback for rounds I and II was obtained from 54/92 and 48/54 approached experts, respectively. There was broad agreement on diagnostic standards, multimodal approaches and focus on adverse events, but uncertainty in terms of pharmacological strategies (including clozapine) in case of failure and antipsychotic dosing in younger patients.

CONCLUSION

Despite knowledge about diagnostic clues and integrated management of EOS, this study highlights the lack of standardization in treating EOS, with safety arguments having a major role in the decision-making process. Targeted clinical trials and systematic dissemination across Europe of current scientific evidence on the value of early intervention services is hoped to contribute to standardized and improved quality care for patients with early-phase psychosis and schizophrenia.