Between 1990 and 2012, the global mean age at diagnosis of autism spectrum disorder ranged from 38 to 120 months. Measures have since been introduced to reduce the age at autism spectrum disorder diagnosis, but the current global mean age is unknown. This review and meta-analysis report the average age at diagnosis from studies published between 2012 and 2019. We initially identified 1150 articles, including 56 studies that reported the mean or median age at diagnosis across 40 countries (n = 120,540 individuals with autism spectrum disorder). Meta-analysis results (on 35 studies, including 55 cohorts from 35 countries, n = 66,966 individuals with autism spectrum disorder) found a current mean age at diagnosis of 60.48 months (range: 30.90–234.57 months). The subgroup analysis for studies that only included children aged ⩽10 years (nine studies, including 26 cohorts from 23 countries, n = 18,134 children with autism spectrum disorder) showed a mean age at diagnosis of 43.18 months (range: 30.90–74.70 months). Numerous factors may influence age at diagnosis and were reported by 46 studies, often with conflicting or inconclusive findings. Our study is the first to ascertain the global average age at autism spectrum disorder diagnosis from a meta-analysis. Continued efforts to lower the average age at autism spectrum disorder diagnosis are needed. Lay abstract We currently assume that the global mean age at diagnosis of autism spectrum disorder ranges from 38 to 120 months. However, this range is based on studies from 1991 to 2012 and measures have since been introduced to reduce the age at autism spectrum disorder diagnosis. We performed a systematic review and meta-analysis (statistical analysis that combines the results of multiple scientific studies) for studies published between 2012 and 2019 to evaluate the current age at autism spectrum disorder diagnosis. We included 56 studies that reported the age at diagnosis for 40 countries (containing 120,540 individuals with autism spectrum disorder). Results showed the current mean age at diagnosis to be 60.48 months (range: 30.90–234.57 months) and 43.18 months (range: 30.90–74.70 months) for studies that only included children aged ⩽10 years. Numerous factors that may influence age at diagnosis (e.g. type of autism spectrum disorder diagnosis, additional diagnoses and gender) were reported by 46 studies, often with conflicting or inconclusive results. Our study is the first to determine the global average age at autism spectrum disorder diagnosis from a meta-analysis. Although progress is being made in the earlier detection of autism spectrum disorder, it requires our constant attention.

The PQ-16 is easy to implement in routine assessment and can be useful to bring up potential psychotic symptoms for further exploration in an early stage, especially in adolescents with low Global Assessment of Functioning scores. The PQ-16 total scores were not confounded by differences in age, gender or disorder. Future research should investigate the true nature of PQ-16 items and whether the item scores and cut-off scores of the PQ-16 in adolescence have any predictive value regarding the development of an ultra high-risk status, a psychotic disorder or other mental disorders.

Professionals' limited knowledge on mental health and their stigmatizing attitudes toward mental illness can delay the diagnosis of autism. We evaluated the knowledge on Autism Spectrum Disorder (ASD) and stigmatizing attitudes in 93 physicians at Dutch Youth and Family Centers (YFC). These physicians screen for psychiatric symptoms in children. We show that their general ASD knowledge scored 7.1 (SD 1.2), but their specific ASD knowledge was only 5.7 (SD 1.7) (weighted means on 1-10 scale, 1 = least knowledge, 10 = most knowledge). Our physicians had positive attitudes toward mental illness (CAMI scores 2.18 (SD 0.33) to 2.22 (SD 0.40) on a 5-point Likert scale) but they had higher levels of stigmatizing attitudes than other Western healthcare professionals. Their levels were considerably lower than in non-Western professionals. We found no relations between ASD knowledge, stigmatizing attitudes and demographic variables. In conclusion, ASD knowledge and stigmatizing attitudes toward mental illness in Dutch YFC physicians require attention.

Children with Autism Spectrum Disorder (ASD) often exhibit problematic eating behaviors, an observation mostly based on male dominated, clinical ASD study samples. It is, however, important to evaluate both children with an ASD diagnosis and children with subclinical autistic traits as both often experience difficulties. Moreover, considering the suggestion of a possible girl-specific ASD phenotype, there is a need to determine whether autistic traits are related with problematic eating behaviors in girls as well. This study explores the sex-specific association between autism (both autistic traits and diagnosed ASD) and eating behavior in middle childhood in Generation R, a prospective population-based cohort from fetal life onwards. We collected parental reports of autistic traits at six years (Social Responsiveness Scale) and of eating behavior at ten years (Children's Eating Behaviour Questionnaire). In this cohort of 3559 children, autistic traits at six years were associated with more Picky Eating, Emotional Eating and Food Responsiveness in later childhood (e.g. adjusted B for Picky Eating = 0.07; 95% CI: 0.03, 0.11). Stratified analyses showed that in girls, autistic traits were associated with more Emotional Overeating and Emotional Undereating (e.g. adjusted B for Emotional Undereating = 0.12; 95% CI: 0.04, 0.20), while no associations were found for boys. Results comparing children with and without an ASD diagnosis in the cohort largely confirm these associations (e.g. in girls, adjusted B for Emotional Undereating = 0.72; 95% CI: 0.01, 1.42). Our results point to a sex-specific association between autism and eating behavior in middle childhood. Also, our study is the first study to show that autistic traits are associated with emotionally based eating problems in girls and possibly represent part of a girl-specific ASD phenotype.