Diagnostic Overshadowing in Autistic Women

Background:

Research indicates that females are diagnosed with Autism Spectrum Disorder (ASD) later than their male counterparts, and that many remain undetected until later in life. Autistic women are likely to experience comorbid mental health conditions, including eating disorders (ED), depression and anxiety, however it is unclear how these conditions impact the accurate detection and diagnosis of ASD.

Objectives:

The aims of this research were to understand how comorbid mental illness interferes with the accurate detection and diagnosis of ASD in women, and how they present now. It was hypothesised that autistic women would not receive a primary diagnosis of ASD, as it would be obscured by the presence of mental health issues, and that autistic women would currently display more severe mental health symptoms than neurotypical women.

Methods:

We recruited 672 women between 18 and 72 years online. The sample contained 350 autistic women (M=36.21 SD=10.10), and 322 neurotypical women (M=34.83, SD=9.93). Self-declared diagnoses were confirmed using the Autism Spectrum Quotient (AQ). Current levels of disordered eating were assessed using the Eating Attitudes Test (EAT-26), and current depression and anxiety symptoms were assessed using the Depression, Anxiety, Stress Scale (DASS-21).

Results:

Chi-square analysis found 32.09% of autistic women had also been diagnosed with an ED χ²_{(1; N=112)} = 7.99, p<.005. Of the 112 autistic women, 86.36% received an ED diagnosis first, with an average of 12.86 years (SD= 9.68) delay before receiving an ASD diagnosis. The average age of ED diagnosis was 17.76 years (SD=6.27) in autistic women, which was not significantly younger than in neurotypical women (p=.480, d =.085.

Chi-square analysis found 82.29% of autistic women had also been diagnosed with either depression or anxiety χ²_{(1; N=288)} = 28.28, p<.001. Of the 288 autistic women, 76.84% received a depression or anxiety diagnosis first, with an average of 13.14 years (SD= 8.98) delay before receiving an ASD diagnosis. The average age of depression or anxiety diagnosis was 19.98 years (SD=7.98) in autistic women, which was significantly younger than in neurotypical women (p=.021, d=.214).

Independent sample t-tests found significant differences in current mental illness symptomology between autistic and neurotypical women in the EAT-26 Total Score (t₍₉₄₂₎=-3.09, p=.005) and Dieting subscale (t₍₉₄₂₎=-3.66, p=<.001), as well as in DASS-21 scores across all subscales: Depression (t₍₆₄₃₎=5.73, p=<.001), Anxiety (t₍₆₄₃₎=8.17, p=<.001), and Stress (t₍₆₄₃₎=7.83, p=<.001). This demonstrates that autistic women currently experience elevated symptomology across many domains.

Conclusions:

Autistic women were more likely to have received a primary diagnosis of a mental illness and not ASD. They faced substantial delays before their ASD was detected and diagnosed. This suggests that diagnostic overshadowing occurred, as ASD symptoms may have been misattributed to, or obscured by comorbid mental illness. Autistic women received some types of mental health diagnoses at an earlier age than neurotypical women, and displayed some current symptoms at a more severe level. It highlights the necessity for greater understanding of female ASD presentation, and the use of female-centric screening tools in women with mental health concerns.