Meta-analysis finds small habenula volume reductions in mood disorders do not survive correction

This meta-analysis examined habenula volume in individuals with mood disorders (major depressive disorder or bipolar disorder) compared to healthy controls. The analysis pooled data from 15 samples, involving 1,230 participants for left habenula analysis and 1,236 for right habenula analysis. The comparator group consisted of healthy controls, with the primary outcome being habenula volume measured via neuroimaging.

In initial, uncorrected analyses, mood disorder patients showed small but statistically significant reductions in habenula volume compared to controls. For the left habenula, the effect size was d = -0.1367 (p = .0344), and for the right habenula, d = -0.1562 (p = .0409). Absolute volume numbers were not reported. However, when statistical correction for multiple comparisons was applied, these group differences were no longer significant. Furthermore, separate meta-analyses for MDD versus controls and bipolar disorder versus controls also showed no significant differences in habenula volume.

Safety and tolerability data were not reported, as this was an observational neuroimaging study. Key limitations include that the primary findings did not withstand correction for multiple comparisons, and no moderator analyses (such as for age, sex, or medication status) yielded significant results. The funding sources and author conflicts of interest were not reported.

In terms of practice relevance, this analysis provides no robust evidence for consistent habenula volume alterations in mood disorders. The findings highlight the methodological challenges in identifying subtle neuroanatomical biomarkers and underscore that observed associations in initial analyses may not represent reliable effects. This evidence does not support the use of habenula volume as a diagnostic marker in clinical practice.