Brain-derived neurotrophic factor genotype is associated with brain gray and white matter tissue volumes recovery in abstinent alcohol-dependent individuals.
Level 3 - non-randomized controlled study
Prospective observational cohort study
PubMed 22989210 · doi:10.1111/j.1601-183X.2012.00854.x
What was done
Treatment-seeking alcohol-dependent individuals were evaluated to determine whether the BDNF Val66Met (rs6265) polymorphism influenced structural brain recovery during early abstinence. Participants underwent 3D T1-weighted MRI at 1.5 T at 1 week of abstinence (n = 62), and a subset was rescanned at 5 weeks of abstinence (n = 41). MRI scans were segmented into gray matter, white matter, and cerebrospinal fluid volumes. BDNF genotype was determined from blood samples using TaqMan assays, and neurocognitive performance was assessed.
What was found
Regional brain tissue volumes were comparable between Val homozygotes and Val/Met heterozygotes at both individual time points. Over the 4-week scan interval, Val homozygotes demonstrated significant gray matter volume increases, whereas Val/Met heterozygotes demonstrated increases predominantly in white matter volume. Longitudinal increases in gray matter volume, but not white matter volume, correlated with improvements in neurocognitive performance. The abstract reports directions of effect but provides no exact numerical values or effect sizes.
Why it matters
This study identifies BDNF genotype as a potential biological factor driving differential tissue recovery during alcohol abstinence, linking gray matter restoration specifically to short-term cognitive improvements.
Limits
The sample size was modest (62 enrolled, 41 followed longitudinally) and suffered from study attrition. The follow-up window was limited to 5 weeks of abstinence. The abstract does not mention a healthy control comparison group, does not report Met/Met homozygotes, and lacks numerical effect sizes and confidence intervals.
Cited by
- supports Former heavy alcohol users can experience a partial recovery of brain white matter after a period of abstinence.