Effects of Bilateral Sequential Theta-Burst Stimulation on 5-HT1A Receptors in the Dorsolateral Prefrontal Cortex in Treatment-Resistant Depression: A Proof-of-Concept Trial

SOURCE: Transl Psychiatry Psychiatry. 13(1):33, 2023 Feb 01.


AUTHORS: Murgas M; Unterholzner J; Stohrmann P; Philippe C; Godbersen GM; Nics L; Reed MB; Vraka C; Vanicek T; Wadsak W; Kranz GS; Hahn A; Mitterhauser M; Hacker M; Kasper S; Lanzenberger R; Baldinger-Melich P

ABSTRACT: Theta-burst stimulation (TBS) represents a brain stimulation technique effective for treatment-resistant depression (TRD) as underlined by meta-analyses. While the methodology undergoes constant refinement, bilateral stimulation of the dorsolateral prefrontal cortex (DLPFC) appears promising to restore left DLPFC hypoactivity and right hyperactivity found in depression. The post-synaptic inhibitory serotonin-1A (5-HT1A) receptor, also occurring in the DLPFC, might be involved in this mechanism of action. To test this hypothesis, we performed PET-imaging using the tracer [carbonyl-11C]WAY-100635 including arterial blood sampling before and after a three-week treatment with TBS in 11 TRD patients compared to sham stimulation (n = 8 and n = 3, respectively). Treatment groups were randomly assigned, and TBS protocol consisted of excitatory intermittent TBS to the left and inhibitory continuous TBS to the right DLPFC. A linear mixed model including group, hemisphere, time, and Hamilton Rating Scale for Depression (HAMD) score revealed a 3-way interaction effect of group, time, and HAMD on specific distribution volume (VS) of 5-HT1A receptor. While post-hoc comparisons showed no significant changes of 5-HT1A receptor VS in either group, higher 5-HT1A receptor VS after treatment correlated with greater difference in HAMD (r = -0.62). The results of this proof-of-concept trial hint towards potential effects of TBS on the distribution of the 5-HT1A receptor. Due to the small sample size, all results must, however, be regarded with caution.

LINK TO FULL ARTICLE: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9892572/