Meta-Analysis of Neuroanatomical Overlap In Autism Spectrum Disorders and Bipolar Disorder

Background: Recently perspectives on neurodevelopmental conditions such as autism spectrum (ASD) have broadened. There is a growing appreciation that what is ‘inherited’ in psychotic disorders such as schizophrenia and bipolar disorder and ASD is not diagnosis specific but rather a neurodevelopmental vulnerability which modifies post-natal brain maturation (Cheung, Yu et al., 2010; van Os and Kapur 2009). Consistent with this, higher rates of bipolar disorder are found in families of individuals with ASD (DeLong 2004). Limbic-striato-thalamic brain regions involved in control of mood and cognition are affected in each condition, but this has not been studied systematically.

Objectives:   To conduct a preliminary anatomical likelihood meta-analytic estimation (ALE, Turkeltaub et al. 2002) ASD and bipolar disorder to establish the extent to which these conditions share a neuroanatomical substrate.

Methods:   We adopted a modified ‘dual-disorder’ ALE technique (Yu, Cheung et al., 2010) to accommodate co-ordinates derived from 15 voxel-based MRI studies of ASD and 19 studies of bipolar disorder in a single analysis. This generated a map of common and distinct regional volume differences in ASD and bipolar disorder.

Results:   Grey matter volumes in bilateral cingulate, left superior, medial, and inferior frontal gyrus, left thalamus were decreased in both bipolar disorder and ASD. Volumes in left caudate, parahippocampal gyrus, middle temporal gyrus, and right precentral and parietal lobe were increased in both conditions. Further detailed analysis to accommodate any potential confounds of age, gender and medication in now underway.

Conclusions:   Our preliminary findings substantiate a sizeable overlap in brain regions affected by both conditions. This may indeed reflect similar neurodevelopmental pressure acting across conditions which is not disorder specific. We suggest further exploration of shared causal factors across a spectrum of neurodevelopmental disorders should be encouraged with an eye to applying advances made in one condition to other related disorders.