Alcohol‐dependent participants showed lower fractional anisotropy (FA) within the corpus callosum compared with healthy controls. This change was negatively associated with lifetime alcohol and nicotine exposure, and there was no evidence of FA recovery despite prolonged abstinence. A group‐by‐age interaction was observed, whereby greater age‐related reductions in FA were evident in AD participants, but no further reductions in FA were observed in alcohol‐polysubstance relative to alcohol‐only‐dependent participants.
