It is never as good the second time around: Brain areas involved in salience processing habituate during repeated drug cue exposure in treatment engaged abstinent methamphetamine and opioid users.

ABSTRACT

The brain response to drug-related cues is an important marker in addiction-medicine. However, the temporal dynamics of this response in repeated exposure to cues are not well known. In an fMRI drug cue-reactivity task, the presence of rapid habituation or sensitization was investigated by modeling time and its interaction with condition (drug>neutral) using an initial discovery-sample. Replication of this temporal response was tested in two other clinical populations all abstinent during their early recovery (treatment). Sixty-five male participants (35.8 ± 8.4 years-old) with methamphetamine use disorder (MUD) were recruited as the discovery-sample from an abstinence-based residential treatment program. A linear mixed effects model was used to identify areas with a time-by-condition interaction in the discovery-sample. Replication of these effects was tested in two other samples (29 female with MUD from a different residential program and 22 male with opioid use disorder from the same residential program as the discovery sample). The second replication sample was re-tested within two weeks. In the discovery-sample, clusters within the VMPFC, amygdala and ventral striatum showed both a main effect of condition and a condition-by-time interaction, indicating a habituating response to drug-related but not neutral cues. The estimates for the main effects and interactions were generally consistent between the discovery and replication-samples across all clusters. The re-test data showed a consistent lack of drug > neutral and habituation response within all selected clusters in the second cue-exposure session. The VMPFC, amygdala and ventral striatum show habituation in response to drug-related cues which is consistent among different clinical populations. This habituated response in the first session of cue-exposure and lack of reactivity in the second session of exposure may be important for informing the development of cue-desensitization interventions.