19525
Correlations Between Depression and Anxiety Scores and Subcortical Regional Volumes in Autism Spectrum Disorder
Comorbid conditions such as depression and anxiety (including obsessive-compulsive disorder (OCD)) are common among individuals with Autism Spectrum Disorder (ASD) with prevalence estimates of around 31% and 42% respectively (Joshi et al. 2013; Gjevik et al. 2011). Certain biological pathways, including subcortical brain regions, have previously been linked to anxiety and depression as well as to core symptoms of ASD (Ecker et al. 2012). Whether the biological pathways mediating symptoms of anxiety and/or depression in individuals with ASD resemble the pathways in non-ASD individuals is currently unknown. The identification of biological mechanisms mediating similar symptoms across a range of disorders is essential given the need to understand common vs distinct disease pathways.
Objectives:
The objective of this study was therefore to examine the neuroanatomical associates of depression and anxiety in individuals with ASD and typically developing controls. Specifically, we focussed on subcortical brain regions.
Methods:
We included 112 right-handed males (67) and females (45) with ASD (mean age 26 years, mean FSIQ 110), and 126 typically developing healthy (73 males and 53 females; mean age 28 years, mean FSIC 117). High-resolution structural T1-weighted MRI images were acquired for all participants. The FreeSurfer image analysis suite was used for data pre-processing and automatic segmentation of subcortical regions, including amygdala, hippocampus, putamen, caudate, thalamus, pallidum and accumbens area. Between-group differences in volumes of individual subcortical regions were examined via a generalized linear model, controlling for total brain volume. Furthermore, we examined the relationship between subcortical volumetric measures and the severity of anxiety and depressive symptoms as measured by the Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and the Obsessive-Compulsive Inventory - Revised (OCI-R).
Results:
Individuals with ASD had a significantly increased volume of the right caudate (F (14, 220) = 4.9, p = 0.03), the left putamen (F (14, 220) = 6.2, p = 0.01), the total putamen (F (14, 220) = 5.1, p = 0.02), and the left nucleus accumbens (F (14, 220) = 5.7, p = 0.02). Also there were significant interactions between diagnosis and BAI scores in volume of the left thalamus (F (14, 211) = 3.9, p = 0.05) and right thalamus (F (14, 211) = 5.8, p = 0.02), and the left putamen (F (14, 211) = 4.1, p = 0.04) and right putamen (F (14, 211) = 5.0, p = 0.03). In right thalamus there was also a significant interaction between diagnosis and OCI-R scores (F (14, 211) = 8.6, p = 0.004).
Conclusions:
To our knowledge, this is the first study to provide proof of concept that biological differences in brain development may underpin both core symptoms of ASD and the severity of commonly co-occuring mental health symptoms.