The effects of gender and age on repetitive and/or restricted behaviors and interests in adults with autism spectrum disorders and intellectual disability

Sex differences in autism spectrum disorders

PURPOSE OF REVIEW

A strong male bias in autism spectrum disorder (ASD) prevalence has been observed with striking consistency, but no mechanism has yet to definitively account for this sex difference. This review explores the current status of epidemiological, genetic, and neuroendocrinological work addressing ASD prevalence and liability in males and females, so as to frame the major issues necessary to pursue a more complete understanding of the biological basis for sex-differential risk.

RECENT FINDINGS

Recent studies continue to report a male bias in ASD prevalence, but also suggest that sex differences in phenotypic presentation, including fewer restricted and repetitive behaviors and externalizing behavioral problems in females, may contribute to this bias. Genetic studies demonstrate that females are protected from the effects of heritable and de-novo ASD risk variants, and compelling work suggests that sex chromosomal genes and/or sex hormones, especially testosterone, may modulate the effects of genetic variation on the presentation of an autistic phenotype.

SUMMARY

ASDs affect females less frequently than males, and several sex-differential genetic and hormonal factors may contribute. Future work to determine the mechanisms by which these factors confer risk and protection to males and females is essential.

How do researchers define self-injurious behavior?

Self-injurious behavior is commonly observed among persons with intellectual disabilities. However, a second parallel use of this term is used in the general mental health field for self-mutilation. The authors describe these two disorders and how they differ. Characteristics of what we refer to as repetitive self-injurious behavior among persons with intellectual disabilities and risk factors for these behaviors are discussed. We also describe different assessment/testing methods which aid in defining this phenomenon. The implications of these data for research and clinical practice are discussed.

Annual research review: re-thinking the classification of autism spectrum disorders

BACKGROUND

The nosology of autism spectrum disorders (ASD) is at a critical point in history as the field seeks to better define dimensions of social-communication deficits and restricted/repetitive behaviors on an individual level for both clinical and neurobiological purposes. These different dimensions also suggest an increasing need for quantitative measures that accurately map their differences, independent of developmental factors such as age, language level and IQ.

METHOD

Psychometric measures, clinical observation as well as genetic, neurobiological and physiological research from toddlers, children and adults with ASD are reviewed.

RESULTS

The question of how to conceptualize ASDs along dimensions versus categories is discussed within the nosology of autism and the proposed changes to the DSM-5 and ICD-11. Differences across development are incorporated into the new classification frameworks.

CONCLUSIONS

It is crucial to balance the needs of clinical practice in ASD diagnostic systems, with neurobiologically based theories that address the associations between social-communication and restricted/repetitive dimensions in individuals. Clarifying terminology, improving description of the core features of ASD and other dimensions that interact with them and providing more valid and reliable ways to quantify them, both for research and clinical purposes, will move forward both practice and science.

Scaling methods to measure psychopathology in persons with intellectual disabilities

Psychopathology prior to the last four decades was generally viewed as a set of problems and disorders that did not occur in persons with intellectual disabilities (ID). That notion now seems very antiquated. In no small part, a revolutionary development of scales worldwide has occurred for the assessment of emotional problems in persons with ID. The first standardized test to emerge was the Psychopathology Instrument for Mentally Retarded Adults (PIMRA) in 1984. Since that time, an impressive number of measures of general psychopathology have emerged for adults and children as well as for persons across the full range of levels of ID. The purpose of this review was to provide a description of available measures, to review papers published on these measures, and to discuss emerging trends in test development. The trends in this body of information for enhancing differential diagnosis of psychopathology in persons with ID are discussed.