In a small longitudinal fMRI study, sexual pictures produced greater activation than methamphetamine and neutral pictures in selected regions at the later abstinence assessment. Clear direct differences between the early and later assessments were not established in those regional comparisons.
Yan and colleagues analyzed 20 adults with methamphetamine dependence after excluding two participants for excessive motion. Scans occurred during short-term abstinence, ranging from one week to three months, and again during long-term abstinence, ranging from ten to fifteen months. Participants viewed methamphetamine-related, sexual and neutral images.
This was human observational follow-up during rehabilitation, not a controlled methamphetamine-dosing experiment. A supplementary healthy comparison group was also examined, but was not well matched on several demographic and substance-use characteristics.
Whole-brain analyses identified five occipital and parietal regions with an abstinence-stage-by-cue-condition interaction. At the later assessment, sexual-cue activation exceeded activation for the other two cue types in those regions. However, the paper reported no clear evidence for direct differences between abstinence stages in the regional follow-up comparisons.
That pattern should not be simplified into a demonstrated decline in drug-cue sensitivity or a proven return to normal sexual reward processing. A difference among cue types within one assessment answers a different question from a reliable change in a particular cue response over time.
The small sample, imaging-motion exclusions and imperfect healthy-group matching constrain interpretation. Self-reported impulsivity changed over follow-up, but associations between questionnaire scores and regional signals do not establish a causal mechanism. Some signed correlation descriptions in the paper also require care because the text and displayed coefficient signs are inconsistent.
The experiment measured responses to pictures, not actual sexual behavior or prospective relapse. Its imaging signals were not concentrations of methamphetamine or amphetamine in a biological specimen, and they do not establish individual intoxication. The useful result is a cue-specific pattern that warrants replication with larger, well-matched longitudinal samples.
Read our analysis of the timing of drug-cue responses during an fMRI scan.
Neurofunctional changes related to methamphetamine and sexual cues in methamphetamine dependence from short- to long-term abstinence. doi:10.1111/adb.13405.