Background and Aims:

Temporal lobe epilepsy (TLE) is frequently associated with major depressive disorder (MDD). Since the amygdala plays a role in both disorders and T2-signal changes might translate gliotic dysfunction, we measured the T2-signal in TLE regarding MDD and antiseizure drugs (ASD) response, as it might help understand the coexistence of these diseases.

Methods:

We included 119 individuals: MDD*responsive (n=10), MDD*ASD-resistant (n=19), no-MDD*responsive (n=12), no-MDD*ASD-resistant (n=17), MDD-only (n=26) and controls (n=35). Using Aftervoxel (http://www.bergo.eng.br/academic/aftervoxel/), we performed relaxometry in T2 coronal multi-echo images (two slices of 3-mm thick) acquired at 3T MRI-scanner. MDD diagnosis followed DSM-V criteria. We performed generalized linear model with log link function, including MDD and pharmacoresponse as main effects and MDD*pharmacoresponse interaction. We tested the relationship between ipsilateral T2-signal and Beck Depression Inventory (BDI) using partial correlations, controlling for scholarity, age and seizure frequency. We set p<0.05 as significant.

Results:

We found independent effects of MDD and pharmacoresponse in the ipsilateral T2-signal (both p<0.001), namely: increased ipsilateral T2-signal in MDD*responsive, MDD*ASD-resistant, no-MDD*responsive and no-MDD*ASD-resistant compared to controls (all p<0.004); in MDD*ASD-resistant (p<0.001) compared to no-MDD*responsive; in MDD*responsive, MDD*ASD-resistant and no-MDD*ASD-resistant compared to MDD-only (all p<0.001). Regarding contralateral amygdala, there was an effect of pharmacoresponse (p<0.001), but no MDD (p=0.53) nor pharmacoresponse*MDD effects, with increased T2-signal in responsive and ASD-resistant patients compared to controls (p<0.01), regardless MDD presence. Greater BDI correlated with increased T2-signal (r=0.31 p=0.03) in TLE group.

Conclusions:

Our data suggest a bilateral effect of pharmacoresponse and only ipsilateral of MDD in amygdalar T2-signal in TLE.

Acknowledgement: FAPESP 2019/08390-9 and 2013/07559-3