Prevalence of co-occurring mental health diagnoses in the autism population: a systematic review and meta-analysis.

Autism spectrum disorder is a construct used to describe individuals with a specific combination of impairments in social communication and repetitive behaviours, highly restricted interests and/or sensory behaviours beginning early in life. The worldwide prevalence of autism is just under 1%, but estimates are higher in high-income countries. Although gross brain pathology is not characteristic of autism, subtle anatomical and functional differences have been observed in post-mortem, neuroimaging and electrophysiological studies. Initially, it was hoped that accurate measurement of behavioural phenotypes would lead to specific genetic subtypes, but genetic findings have mainly applied to heterogeneous groups that are not specific to autism. Psychosocial interventions in children can improve specific behaviours, such as joint attention, language and social engagement, that may affect further development and could reduce symptom severity. However, further research is necessary to identify the long-term needs of people with autism, and treatments and the mechanisms behind them that could result in improved independence and quality of life over time. Families are often the major source of support for people with autism throughout much of life and need to be considered, along with the perspectives of autistic individuals, in both research and practice.

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Autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted interests and repetitive behaviors. There have been recent concerns about increased prevalence, and this article seeks to elaborate on factors that may influence prevalence rates, including recent changes to the diagnostic criteria. The authors review evidence that ASD is a neurobiological disorder influenced by both genetic and environmental factors affecting the developing brain, and enumerate factors that correlate with ASD risk. Finally, the article describes how clinical evaluation begins with developmental screening, followed by referral for a definitive diagnosis, and provides guidance on screening for comorbid conditions.

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Autism spectrum disorder: definition, epidemiology, causes, and clinical evaluation.

Autism Spectrum Disorder (ASD) is one of the most prevalent neurodevelopmental disorders, affecting an estimated 1 in 59 children. ASD is highly genetically heterogeneous and may be caused by both inheritable and de novo gene variations. In the past decade, hundreds of genes have been identified that contribute to the serious deficits in communication, social cognition, and behavior that patients often experience. However, these only account for 10-20% of ASD cases, and patients with similar pathogenic variants may be diagnosed on very different levels of the spectrum. In this review, we will describe the genetic landscape of ASD and discuss how genetic modifiers such as copy number variation, single nucleotide polymorphisms, and epigenetic alterations likely play a key role in modulating the phenotypic spectrum of ASD patients. We also consider how genetic modifiers can alter convergent signaling pathways and lead to impaired neural circuitry formation. Lastly, we review sex-linked modifiers and clinical implications. Further understanding of these mechanisms is crucial for both comprehending ASD and for developing novel therapies.

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Genetic Causes and Modifiers of Autism Spectrum Disorder

Camouflaging entails 'masking' in or 'passing' social situations. Research suggests camouflaging behaviours are common in autistic people, and may negatively impact mental health. To enhance understanding of camouflaging, this study examined reasons, contexts and costs of camouflaging. 262 autistic people completed measures of camouflaging behaviours, camouflaging contexts (e.g. work vs. family), camouflaging reasons (e.g. to make friends) and mental health symptoms. Findings indicated a gender difference in reasons for camouflaging, with autistic women more likely to endorse "conventional" reasons (e.g. getting by in formal settings such as work). Both camouflaging highly across contexts and 'switching' between camouflaging in some contexts but not in others, related to poorer mental health. These findings have implications for understanding camouflaging in autistic adults.

https://link.springer.com/content/pdf/10.1007/s10803-018-03878-x.pdf

Understanding the Reasons, Contexts and Costs of Camouflaging for Autistic Adults.

Objective To derive the first systematically calculated estimate of the relative proportion of boys and girls with autism spectrum disorder (ASD) through a meta-analysis of prevalence studies conducted since the introduction of the DSM-IV and the International Classification of Diseases, Tenth Revision . Method Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The Medline, Embase, and PsycINFO databases were searched, and study quality was rated using a risk-of-bias tool. Random-effects meta-analysis was used. The pooled outcome measurement was the male-to-female odds ratio (MFOR), namely the odds of being male in the group with ASD compared with the non-ASD group. In effect, this is the ASD male-to-female ratio, controlling for the male-to-female ratio among participants without ASD. Results Fifty-four studies were analyzed, with 13,784,284 participants, of whom 53,712 had ASD (43,972 boys and 9,740 girls). The overall pooled MFOR was 4.20 (95% CI 3.84–4.60), but there was very substantial between-study variability (I 2  = 90.9%). High-quality studies had a lower MFOR (3.32; 95% CI 2.88–3.84). Studies that screened the general population to identify participants regardless of whether they already had an ASD diagnosis showed a lower MFOR (3.25; 95% CI 2.93–3.62) than studies that only ascertained participants with a pre-existing ASD diagnosis (MFOR 4.56; 95% CI 4.10–5.07). Conclusion Of children meeting criteria for ASD, the true male-to-female ratio is not 4:1, as is often assumed; rather, it is closer to 3:1. There appears to be a diagnostic gender bias, meaning that girls who meet criteria for ASD are at disproportionate risk of not receiving a clinical diagnosis.

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What Is the Male-to-Female Ratio in Autism Spectrum Disorder? A Systematic Review and Meta-Analysis

Importance Avoidant restrictive food intake disorder (ARFID) is a newly recognised eating disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and in the International Classification of Diseases, Eleventh Revision which shows great heterogeneity in its clinical presentation. Objectives Here, we examined the clinical characteristics of ARFID and explored the associations between ARFID symptoms and traits of anxiety. We also investigated whether individuals with ARFID show a different clinical presentation based on their biological sex or comorbid autism spectrum disorder (ASD) diagnosis. Design, Setting, and Participants We recruited 261 consecutive patients from the specialised ARFID outpatient service at the Maudsley Centre for Child and Adolescent Eating Disorders, Michael Rutter Centre, Maudsley Hospital, London, United Kingdom. Main Outcomes and Measures The parents of the patients completed the Pica, ARFID, Rumination Disorder - ARFID - Questionnaire (PARDI-AR-Q), the Revised Children's Anxiety and Depression Scale (RCADS) and reported biological sex of their offspring. Age, height, and weight were obtained from medical records. Clinicians reported on comorbid ASD diagnosis and anxiety traits using the Current View Tool. Results This cross-sectional study included 261 child and adolescent ARFID patients (133 [51%] female) with a median age of 12.7 years (IQR=9.2 to 15.8). Patients' BMI-for-age z-scores ranged from -6.75 to 4.07 (median = -1.07, IQR = -2.25 to -0.01). Patients' comorbid traits of anxiety had the highest correlations with symptoms on the concern about aversive consequences driver of ARFID: panic disorder correlated with physical feelings of panic and anxiety when eating (r=0.53, p=7.74 x 10-31) and being afraid to eat (r=0.42, p=5.13 x 10-21); generalised anxiety correlated with physical feelings of panic and anxiety when eating (r=0.44, p=7.72 x 10-23); and separation anxiety correlated with avoiding eating situations (r=0.36, p=2.01 x 10-15). Sensory sensitivity to the appearance of food positively correlated with separation anxiety (r=0.40, p=1.52 x 10-16) and generalised anxiety (r=0.36, p=7.16 x 10-18). The sensory sensitivities (RR = 0.96; 95% CI, 0.85 to 1.09; P = .53), lack of interest (RR = 1.14; 95% CI, 1.03 to 1.28; P = .02) and concern about aversive consequences (RR = 1.27; 95% CI, 1.03 to 1.56; P = .03) drivers were independent of patient sex. Comorbid ASD was reported in 74 (28%) ARFID patients. Their parents reported higher rates of food-related sensory sensitivities (RR = 1.26; 95% CI, 1.09 to 1.45; P=0.002) and lack of interest (RR = 1.19; 95% CI, 1.05 to 1.34; P=0.006) driving their child's avoidant and restrictive eating than parents of ARFID patients without ASD (127 [49%]). Conclusions and Relevance Our study highlights that ARFID patients present with varying combinations and severity of food-related sensory sensitivities, lack of interest and concern about aversive consequences which drive their avoidant and restrictive eating. ARFID does not discriminate between male and female children and adolescents or those with or without ASD. Anxiety and ASD can co-occur with ARFID, and ASD may accentuate food-related sensory sensitivities and lack of interest. Healthcare professionals should be aware of the multi-faceted and heterogenous nature of ARFID; it is important that comprehensive multidisciplinary assessments are administered to sufficiently understand the drivers of the eating behaviour and associated physical health, nutritional, and psycho-social risk and impact.

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Rachel Loomes

Papers

What Is the Male-to-Female Ratio in Autism Spectrum Disorder? A Systematic Review and Meta-Analysis

The clinical presentation of avoidant restrictive food intake disorder is largely independent of sex, autism spectrum disorder and anxiety traits