Autism spectrum disorder (ASD) is recognised as a predominantly male disorder with associated co-morbid mental health difficulties. There is a large body of literature that includes male children with ASD. However, there is limited investigation of co-morbid difficulties of adults with ASD, and in particular, female adults.
The primary objective of this study is to elucidate the prevalence and type of co-morbid mental health disorders in adult males and females with ASD.
A retrospective review was completed of 527 adult patients (78% male; mean age: 31years, SD: 12 years and 22% female; mean age: 31years, SD: 10years) diagnosed with ASD at the Behavioural Genetics Clinic, a specialist clinic providing gold-standard assessment of ASD in adults at the Maudsley Hospital, London. Diagnostic assessment included a detailed neuropsychiatric interview, the Autism Diagnostic Observation Schedule (ADOS) and / or Autism Diagnostic Interview-Revised (ADI-R), depending on consent to contact parents/ parental availability, and a physical examination. Co-morbid mental health diagnoses were made in accordance with ICD10 criteria (with the exception of adult Attention Deficit Hyperactivity Disorder (ADHD), which was assessed using DSM IV, in line with UK guidelines.
60% of men and 49% of women diagnosed with ASD also met diagnostic criteria for at least one other co-morbid mental health condition. The most common of these was depression in men (22% compared to 17% women), and Generalised Anxiety Disorder in women (18% compared to 12% in men). Obsessive Compulsive Disorder was diagnosed in 18.9% and 16.4% of men and women respectively. The occurrence of social phobia (11%) and Agoraphobia (9%) was the same for both groups.
The rates of different co-morbid conditions were contrasted between the genders using Pearson’s chi-square test. The most striking difference between male and female groups was in Schizophrenia and Psychosis. Over 4% of men received a confirmed diagnosis of Schizophrenia or Psychosis, but these disorders were not confirmed in any women (p = 0.04). However, a significantly higher fraction of women (3.4%, in comparison to only 0.25% of men) exhibited psychotic features related to depression and /or other mood disorders, or sub-threshold psychotic features (p = 0.009). There were no significant differences in rates of any other co-morbid conditions between the genders.
These results show a high incidence of co-morbid affective disorders (depression/ anxiety/OCD) in both male and female adults with ASD, but suggest a gender difference in vulnerability to psychosis in adult males. Our findings have both clinical and health economic implications for service development and treatment, and highlight the need for improved recognition and treatment of co-morbid mental health difficulties in both adult males and females with ASD.
See more of: Epidemiology
See more of: Prevalence, Risk factors & Intervention