Ageing and Autism Spectrum Disorder: Symptom Severity, Life Outcome and Additional Mental Health Conditions in Adults Coming for First Diagnosis

Background: Recent studies suggest the prevalence of Autism Spectrum Disorder (ASD) in adults equals that found in children, approximating 1% in the last UK ONS Household survey (Brugha et al., 2011).  Although ASD is assumed to be a lifelong condition, the majority of research studies focus on children or young adults (Mukaetova-Ladinska et al., 2011), and very little is known about changes in old age in ASD (Happe & Charlton, 2010; Perkins & Berkman, 2012).

Objectives: To gather more information about the pattern of autism symptom severity, life outcome and additional mental health conditions in older versus younger adults with ASD receiving first-diagnosis in adulthood.

Methods: Clinical case records were analysed from adults (N=100; aged 18 to 70, mean= 40 years) referred to an adult ASD diagnostic clinic to be assessed for a possible ASD diagnosis. Group comparisons between younger (aged 18 to 38, mean= 24 years) and older adults (aged 50 to 70, mean= 56 years) were made, for those individuals who did and those who did not receive an ASD diagnosis. ASD symptoms, life outcome (i.e. education, employment, independence, close relationships, and friendship), and additional psychiatric disorders were compared for younger and older adults, and in relation to age across the group.

Results: A third of adults with ASD had fair or poor life outcome, despite all having at least average intellectual functioning.Old adults with ASD had better close relationships, employment, and independence compared to the younger group, whereas ASD symptom severity, friendship, and educational outcome did not differ by age. The same pattern of age differences was seen in the non-ASD group except for employment. Additional psychiatric problems were common in both age groups with ASD, while there was a higher incidence of anxiety (56%) and depression (42%) in the old group compared to young adults. Other additional psychiatric conditions seen in old adults with ASD were OCD, ADHD, personality disorders, bipolar disorder, and harmful use of alcohol. Among the young individuals with ASD those who had OCD as an additional diagnosis had more severe rigid and repetitive behaviours and interests than those without additional mental health conditions.

Conclusions: This study represents an exploratory and preliminary step to fill the huge gap in the ASD literature concerning ageing. Limitations, implications and future research will be considered.