Gender Differences in Misdiagnosis and Delayed Diagnosis among Adults with Autism Spectrum Disorder with No Language or Intellectual Disability

Autism Spectrum Disorder (ASD) is often unrecognized, especially in mild forms and in women. Studies evaluating features associated with missed/misdiagnosis in men and women with ASD are warranted. 61 subjects (22 females, 39 males, age 28.5 ± 10.8 years) with ASD with no language/intellectual deficit were enrolled in the service for the treatment of psychiatric comorbidities in adults with ASD of the ASST Fatebenefratelli-Sacco in Milan (Italy). A detailed clinical history was gathered, and two self-report questionnaires (Autism Spectrum Quotient-AQ and Adult Autism Subthreshold Spectrum-AdAS Spectrum) were administered. 75.4% received their ASD diagnosis average eight years later than the first evaluation by mental health services. Compared to males, females showed a significantly greater delay in referral to mental health services and a significantly higher age at diagnosis of ASD. Among men, diagnostic delay inversely correlated with scores on the AdAS Spectrum total, Verbal communication, Empathy and Inflexibility and adherence to routine domains. Among women, diagnostic delay positively correlated with the Attention to detail score while the age at diagnosis of ASD positively correlated with the AdAS Spectrum Verbal communication and Restricted interests and rumination domain scores. Females were less likely to be correctly diagnosed and more likely to be misdiagnosed at first evaluation than men. Females reported significantly higher scores than men in the Hyper/Hyporeactivity to sensory input domain only among subjects who were misdiagnosed. Our findings provide gender-specific information about ASD patients seeking help for comorbid conditions and might be a primary ground for future research.