Dorsal Anterior Cingulate Cortical Thickness Is Associated with Improvement in Worry Severity Following Treatment in Late-Life Generalized Anxiety Disorder

We recently showed that late-life participants with generalized anxiety disorder (GAD), compared with non-anxious elderly, had lower cortical thickness in the dorsal anterior cingulate cortex (ACC) and the orbitofrontal cortex (OFC). In this follow-up study, we investigated the association between cortical thickness and clinical markers of treatment response in a subgroup from that same sample. Twelve GAD participants were randomly selected and were included in an open label twelve-week treatment with citalopram and pre-/post-treatment magnetic resonance imaging (MRI). Cortical thickness measurements were obtained with Freesurfer. Six regions were selected based on previous results: left dorsal ACC, left rostral ACC, left and right medial orbitofrontal, right pars triangularis and right pars opercularis. A two-tailed paired t-test (non-parametric Wilcoxon Signed Rank test) was used to compare pre- and post-treatment for all clinical variables. For each region of interest (ROI), the Pearson correlation coefficient was estimated between pre-treatment cortical thickness and change in Penn State Worry Questionnaire (PSWQ) from pre- to post-treatment. Our results indicate that greater left pre-treatment dorsal ACC cortical thickness was associated with improvement in worry severity post-treatment. In late-life GAD, greater treatment response is associated with greater cortical thickness in areas pivotal for emotion regulation.