Anxiety and Depression from Adolescence to Old Age in Autism Spectrum Disorder

Background: Most research on anxiety and depression in autism spectrum disorder (ASD) has focused on children and adolescents. In the general population, anxiety and depression show distinct trajectories across the lifespan with increasing negative impact on functioning over time. As ASD is a lifelong condition, it is important to understand the rates, presentation, and impact of anxiety and depression across different developmental periods, especially from adolescence into young and middle adulthood and beyond.

Objectives: The first aim of the current study was to examine age trends in anxious and depressive symptoms from older adolescence to middle and older adulthood, in a large, cross-sectional sample of adolescents and adults with ASD. The second aim was to examine the association between anxious and depressive symptomatology and other individual characteristics, including gender and ASD symptom severity, as well as socio-economic factors relating to education level and current employment status.

Methods: 255 adolescents and adults with ASD (151 males, 59.2%; M_age= 33.52 years, SD= 14.98, range: 14.29-80.16 years) completed the Abridged Version of the Autism-Spectrum Quotient (AQ-28), DSM-5 Dimensional Anxiety Scale (DSM-5 DAS) and the Patient Health Questionnaire-9 (PHQ-9) to assess self-reported ASD, anxiety and depression symptoms respectively. Participants were recruited through three Australian studies: the Longitudinal Study of Australian School Leavers with Autism, the Australian Longitudinal Study of Adults with Autism, and the Dandelion Program.

Results: More than one-third of participants reported clinically elevated anxiety (38.4%) or depression (38%). There were no differences between adolescents (15-19 years), young adults (20-39 years), middle-age (40-64 years), and old age (65+ years) adults in anxiety raw scores (F= 1.50, p= .21, ηp² = .018) but there were statistically significant differences in depression (F= 2.77, p= .042, ηp²= .032), with post-hoc comparison showing that individuals in the middle-aged group had significantly higher depression scores than individuals in the adolescent age group (p= .04, Cohen’s d= .45, BCa 95CI [-5.89, -.08]). There were no group differences in the proportion of individuals who scored above or below the clinical cut-off scores for depression, χ²= 5.40, p= .14, Phi= .145, or anxiety, χ²= 3.01, p= .39, Phi= .109 Linear regression models were used to explore predictors of anxiety and depression. For anxiety, the overall model explained 10.7% of variance, F = 15.05, p < .001, with female gender (β= .16, t= 2.56, p= .011) and higher AQ total score (β= .23, t= 3.68, p < .001) being unique significant independent predictors of higher anxiety symptom severity. For depressive symptomatology, the regression model explained a total of 15.5% of the variance, F = 11.51, p < .001, with female gender (β= .21, t= 3.33, p= .001) and higher AQ total score (β= .27, t= 4.04, p < .001) also independently predicting depression.

Conclusions: Findings from our study provide evidence that both anxiety and depression are highly prevalent across the lifespan in individuals with ASD and emphasise the need to provide a timely and accurate assessment of these co-occurring symptoms in young, middle and older adulthood.