The path from brain to words is rerouted in opioid addiction

Whether spontaneous speech preserves how the brain encoded an experience is unknown. We tested this question in opioid use disorder (OUD), in which drug cues outweigh other rewards. Eighty-two people with OUD and 34 controls watched the opening of the film Trainspotting during functional magnetic resonance imaging, then retold it in their own words. Language-model analyses showed that people with OUD dwelt on craving, personal identification and recovery, devoting more of their retelling to drug scenes. In 65 participants with imaging, this speech bias tracked how strongly the brain had distinguished drug from non-drug scenes during viewing, in left frontoparietal cortex in controls but left temporal cortex in OUD. Direct comparison showed left accumbens coupling positive in OUD and negative in controls, and left superior frontal coupling weaker in OUD. Spontaneous speech thus carries a trace of neural encoding whose route depends on what the experience meant to the speaker.