Assessing the Effect of Abstinent Duration on Brain Function in Heroin‐Dependent Individuals During Protracted Abstinence: A Resting‐State fMRI Study

Protracted abstinence (PA) is the commonly implemented treatment of heroin-dependent individuals (HDIs) in China. However, the effect of abstinence duration on the brain function of HDIs during PA using resting-state functional magnetic resonance imaging (fMRI) remains unclear. Fourteen HDIs who had finished PA for about 6 months (PA6), 16 HDIs who had completed PA for about 11 months (PA11) and 15 demographically matched healthy controls (HC) underwent this fMRI study. We analysed the difference in amplitude of low-frequency fluctuation (ALFF) values among the three groups. Then we analysed the difference in functional connectivity (FC) based on the differential regions of ALFF. Additionally, we examined the relationship between FC of differential brain regions and abstinence duration. The differences in ALFF among the three groups were found to be significant in the bilateral putamen and left inferior parietal lobule (single voxel p < 0.001, cluster level p < 0.05 and GRF-corrected). Compared with the PA6 group, the PA11 group showed lower ALFF values of the differential regions with a tendency toward the HC group. Meanwhile, the PA11 group showed lower FC between the left putamen and left insula, between the right putamen and left insula and between the left inferior parietal lobule and bilateral inferior frontal gyrus (IFG), but higher FC between the left putamen and left inferior temporal gyrus. The above FC of HDIs negatively correlated with the abstinence duration, except for the left putamen-inferior temporal gyrus FC. The prolonged abstinence duration may be useful to restore the impaired brain function of HDIs to some extent, although more data are needed to validate this in future studies.