Female autism phenotypes : sex/gender differences in functioning, camouflaging, and eating problems

Abstract

Background: Autism is a neurodevelopmental condition defined by challenges in social interaction and communication and presence of repetitive patterns in behavior, interests, and activities alongside sensory processing alterations (RRBI). While a long-standing tenet of autism is a male predominance of the condition, recent research evidence indicate that autistic females are diagnosed late or even missed, limiting timely access to support, and potentially increasing the risk of mental health problems and reduced quality of life (QoL). Evidence also suggests elevated risks of other detrimental outcomes among autistic females, including suicide and internalizing mental health problems, although findings regarding the latter have been inconsistent. Research further characterizing female autism phenotypes and challenges in this group is warranted.

Aims: The overarching aim of this thesis was to contribute to deeper insights into female autism phenotypes and associated risk factors for detrimental outcomes, via qualitative exploration of the perception of sex/gender differences in autism among professionals working with autistic people, and via quantitative investigations of eating problems and camouflaging.

Methods: An expert survey exploring the perceptions of functional sex/gender differences in autism in a multi-disciplinary and international sample of professionals was conducted including descriptions of sex/gender-related characteristics pertaining to the individual as well as the environment. In addition, the link between dimensional and categorical operationalizations of autism and eating problems was evaluated including sex/gender moderation of the association, in a thoroughly phenotyped twin sample. Furthermore, a psychometric evaluation of a Swedish version of the Camouflaging Autistic Traits Questionnaire (CAT-Q) was performed, allowing further investigation of the construct. Finally, the hypothesized negative causal effect of camouflaging on QoL was tested using a co-twin control design and within-pair analyses controlling for familial confounding.

Results: Professionals perceived autism manifestations in females as more difficult to recognize due to overall less salient challenges and increased use of behavioral strategies that camouflage autistic characteristics in this group. The investigation of eating problems indicate that problems such as selective eating and sensory issues in mealtimes are present among autistic adolescents and adults, but the association between autistic traits and overall eating problems was especially pronounced in females. Also, eating with others in social situations arose as a specific difficulty experienced by autistic females. The psychometric evaluation of the Swedish version of the CAT-Q (CAT-Q/SE) yielded partial support for the reliability and validity of the scale and indicated that camouflaging behaviors may decline with increasing age in non-autistic people while remaining at elevated levels among autistic people. Camouflaging was significantly associated with reduced QoL, also when controlling for familial factors within dizygotic (DZ) and monozygotic (MZ) twin pairs, consistent with a causal effect.

Conclusions: This thesis found support for sex/gender moderation in areas that are potentially involved in shaping important outcomes among autistic females, including delayed diagnosis, low social participation, and QoL. The findings support that eating problems and camouflaging are prominent in female autism phenotypes and strengthen previous claims of camouflaging strategies having a negative impact on QoL. Addressing eating problems and camouflaging in health care services may facilitate functioning and QoL and could be of relevance among autistic females.