Comparative effects of topiramate and naltrexone on neural activity during anticipatory anxiety in individuals with alcohol use disorder

Topiramate has been found to be effective in reducing alcohol use and may also attenuate anxiety severity in patients with alcohol use disorder (AUD). This study compared the neural response of treatment-seeking patients with AUD on either topiramate or naltrexone during an anticipatory anxiety task. Participants were 42 patients with AUD who were randomized to receive either topiramate (n = 23; titrated dose up to 200 mg/day) or naltrexone (n = 19; 50 mg/day) for 12-weeks as part of a larger randomized controlled trial. Following 6 weeks of treatment, participants completed an anticipatory anxiety task during a functional magnetic resonance imaging (fMRI) session. The task presented a series of high-threat and low-threat stimuli followed by an unpleasant or pleasant image, respectively. Primary whole-brain analyses revealed no significant differences in neural activation between the topiramate and naltrexone groups. Deactivation for safe cues relative to threat cues was observed within the precuneus, inferior parietal lobule and the cingulate gyrus. In the precentral and middle frontal gyri, threat cues elicited greater activation. Exploratory analyses revealed an effect of change in anxiety from baseline to week 6, with a greater reduction associated with a reduced response to threat cues relative to safe cues in the cuneus and lingual gyrus. The current study is the first to examine and compare neural activation during anticipatory anxiety in treatment-seeking individuals on topiramate and naltrexone. This preliminary research contributes to our understanding of the therapeutic mechanisms of these alcohol pharmacotherapies.