RAADS-14 as a screening tool for autism spectrum disorders in adult population
Autism spectrum disorder (ASD) is a range of neurodevelopmental conditions characterized by persisting deficits in social communication and interaction, repetitive and stereotyped behavior, and restricted interests 1. The prevalence of ASD in adult population is steadily increasing, it greatly affects the quality of life of adults with ASD and impairs a significant burden on health and social care 2. Autism in adults with no intellectual impairments is also quite frequent 3, and often underdiagnosed 4, particularly in women 5. Late identification and general underdiagnosis and misdiagnosis of ASD leads to a problem of ‘a lost generation’ of autistic adults with no intellectual impairments 6. The comorbidity of ASD and other neuropsychiatric conditions is quite high 7, differential diagnostics can also pose a problem, therefore proper assessment of autistic traits and related problems can be crucial for increasing the quality of life of people with ASD 8. There is a range of self-report questionnaires available for screening of ASD in adults with no intellectual impairments, the most widely used being: the Autism-Spectrum Quotient (AQ, 50 items) 9 and its shorter versions, AQ-1. AQ-2. and AQ-J-21 10; the Ritvo Asperger and Autism Diagnostic Scale - Revised (RAADS-R, 80 items) 11 and its short version RAADS-14 8; the Social Responsiveness Scale, 2nd edition –Adult form (SRS-A or SRS2-A, 65 items) 12; and the Adult Social Behavior Questionnaire (ASBQ, 44 items) 13. A systematic review found that stronger evidence of good or satisfactory measurement and diagnostic properties exist for AQ-5. AQ-S, and RAADS-R and RAADS-14 10.
The RAADS-14 is a 14-item self-report questionnaire specifically designed to be used as a screening tool for ASD and distributed under CC BY 2.0 Creative Commons License 8. It was developed on the basis of the longer and more comprehensive RAADS-R, which has demonstrated good overall psychometric properties, test-retest reliability, discriminant and convergent validity, sensitivity and specificity 11,14,15. The RAADS-14 was developed using the Swedish version of the RAADS-R 16 and validated on Swedish clinical and non-clinical samples. According to the reported factor structure, the RAADS-14 consists of three factors corresponding to domains of Mentalizing deficits, Social anxiety and Sensory reactivity. All the items are scored on a four-point Likert scale (ranging from 0 to 3) indicating duration of each symptom (3 = ‘true now and when I was young’,2= ‘true only now’,1= ‘true only when I was younger than 16’ and 0 = ‘never true’). Item scores are summed to produce the total score and the subscale scores. The recommended cutoff of 14 for the original English version yielded excellent sensitivity of 0.97 and specificity of 0.95 over non-psychiatric population. The gender differences were moderate: neurotypical males scoring somewhat higher than females in the mentalizing deficits and social anxiety domains, while females scored higher than males in the sensory reactivity domain.
The RAADS-14 is very short and easy to administer and has already demonstrated the potential to distinguish efficiently between ASD and other neuropsychiatric conditions in adult population.
Assessing autistic traits in adult population in Russia: current problems and possible directions
The situation with clinical diagnostics of ASD in adult population in Russia is very problematic, as several historical factors add to the above-mentioned diagnostic issues leading to even greater ASD underdiagnosis in Russian adult population. According to the official statistical data by Rosstat (Russian statistical agency), in 2016 there were only 96 adults officially diagnosed as having ASD (less than .001% of adult population) 17, which is at least 1000 times less than the estimates based on European cohort statistics. This huge disagreement reveals the fact that it was virtually impossible to get an official diagnosis of ASD for high functioning adolescents and adults for two major reasons. The first reason is related to underdiagnosis of ASD in childhood during 1970-2010s which was less pronounced than for adults but still quite prominent: as of 1999, the officially recognized ratio was 1 in 385 18. For children without intellectual impairments the diagnosis was almost never officially established, often in order to help the parents to avoid the stigma 19. The second reason is an almost routine obligatory change of the official clinical diagnosis from ASD to some other neuropsychiatry condition performed when a person reaches adolescence or adulthood, most commonly, to schizoaffective disorder and/or mental retardation, this clinical practice was officially reproved only on the June 30th, 2014 20. On the October 4th, 2017, Russian Ministry of Health issued a letter of instructions (№ 17-1/10/1-6371) explicitly prohibiting an unfounded change of diagnosis from ASD to another mental condition for individuals reaching adulthood, as some psychiatrists tended to adhere to the old diagnosis-switching practice 21. Due to the efforts of governmental and non-governmental institutions, autism professionals, parental community, and autism community it is now widely recognized that ASD in adults is currently underdiagnosed in Russia but implementing the diagnostic routines will have to take some time, and is hindered by the lack of diagnostic tools and trained professionals. The Russian version of ADOS-2 was published only in 2016 22,23, and its adult module still remains under validation.
In this situation, the need for self-assessment tools in the autistic community has long been perceived as high. Despite that, to our best knowledge, no self-assessment tools for evaluating autistic traits and for screening of ASD in adult population or adolescents has been officially developed, adapted, and validated on Russian-speaking samples. Several attempts were made by members of autistic community to provide Russian versions of internationally recognized questionnaires, even if just for a rough reference; the largest collection of unofficial translations (including AQ, RAADS-R, Aspie Quiz, and The Broad Autism Phenotype Test) is presented at a web-site related to autism and to the problems of people with ASD24 developed and maintained by members of Russian autism community. There are multiple anecdotal pieces of evidence that most of these questionnaires used with cut-offs established for European samples tend to overestimate the prominence of autistic traits but no data on this issue have been officially reported.
The lack of ASD diagnostic tools and inventories assessing autistic traits validated on Russian-speaking samples significantly limits the options to assess criterion validity of any emerging ASD screening questionnaire. In order to get additional circumstantial evidence, special efforts could be made to evaluate the questionnaire’s discriminant validity comparing it to other personality trait inventories. There are numerous studies exploring the links between the autism traits and other personality factors and constructs. The Big Five personality model is probably the most well-established general personality construct 25 which was found to strongly relate to autism traits in a large number of studies, consistently revealing moderate positive correlations of ASD scores to neuroticism, and weak to moderate negative correlations to all the other Big Five factors 26. A study utilizing multivariate approaches to explore the relations between IPIP-NEO-120 and RAADS-R scores found that Big Five personality factors accounted for 70 % of variance in autism trait scores 27. These findings suggest that a Big Five personality questionnaire would be a good tool to assist in affirming convergent and discriminant validity of an ASD assessment tool.
Aim and general design of the study
The general aim of our research was to construct and validate a Russian version of the RAADS-14 (the RAADS-14 Rus) to provide the initial reference point in developing the body of instruments for assessing autistic traits in Russian-speaking adult population. This measure was chosen due to its good psychometric characteristics, discriminative properties, and simplicity of use. The study aims to assess the reliability of the RAADS-14 Rus, its factor structure, and to provide the initial estimates of the questionnaire’s validity, diagnostic properties, and potential for use as a screening tool for ASD in adults with no intellectual impairments. We have also formulated three specific research hypotheses:
- The RAADS-14 Rus factor structure would be equivalent or similar to the factor structure of the original Raads-14;
- The RAADS-14 Rus total scores and subscale scores will have weak to moderate correlations to the scores of the Big Five personality factors, in particular, positive to neuroticism and negative to extraversion, consistent to the previous studies;
- The distribution of the RAADS-14 scores could be different for general Russian-speaking population, producing greater mean total score values and yielding potentially higher cutoff scores to provide reasonable specificity of the questionnaire.