Personality Trait Predictive Utility and Stability in Transcranial Magnetic Stimulation (rTMS) for Major Depression: Dissociation of Neuroticism and Self-Criticism: Utilité prédictive et stabilité des traits de personnalité dans la stimulation magnétique transcrânienne répétitive (SMTr) pour la dépression majeure : dissociation du neuroticisme et de l’autocritique

Role of the insula in rTMS response for depression

BACKGROUND

The insula has a significant impact on interoception and depression. This study aims to explore the role of the insula in mediating treatment responses to high-frequency repetitive transcranial magnetic stimulation (rTMS) targeting the left dorsolateral prefrontal cortex (DLPFC).

METHODS

Twenty-five patients with either bipolar disorder (BD, n = 15) or major depressive disorder (MDD, n = 10) were recruited. All subjects were aged between 20 and 70, with a minimum score of 18 on the 24-item Hamilton Rating Scale for Depression (HDRS-24). Each patient received 12 sessions of rTMS treatment using a figure-eight-shaped coil at 10 Hz high-frequency stimulation intensity, targeted to the left DLPFC. Resting-state functional magnetic resonance imaging was conducted before and after the rTMS treatment to assess changes in insula-seeded functional connectivity.

RESULTS

Both BD and MDD patients experienced significant reductions in depressive symptoms following rTMS therapy. The respective response rates at weeks 4, 8 and 12 were 64.0 %, 64.0 % and 68.0 % and remission rates were 40.0 %, 36.0 % and 44.0 %. Decreases in functional connectivity between the right anterior insula and right calcarine were significantly larger in the remitters than in the non-remitters (p = 0.013). Additionally, a higher baseline functional connectivity between the right anterior insula and right superior temporal gyrus correlated with better treatment outcome.

LIMITATIONS

The small sample size of 25 participants is small.

CONCLUSION

Our findings highlight the potential role of the insula in depression and suggest that insula-seeded functional connectivity could serve as a predictive biomarker for rTMS efficacy.

Self-criticism predicts antidepressant effects of intermittent theta-burst stimulation in Major Depressive Disorder

BACKGROUND

Self-criticism is a risk factor for depression and depressive symptom persistence, however higher degrees of self-criticism have been associated with greater antidepressant benefits from repetitive transcranial magnetic stimulation (rTMS), suggesting that self-criticism may act as a proxy for function of the targeted circuit. We test this hypothesis using secondary data from an rTMS treatment trial where an NMDA receptor agonist (D-Cycloserine) was used to enhance TMS synaptic plasticity to improve efficacy. We hypothesized that self-criticism would be more strongly associated with treatment outcome when stimulation was paired with D-Cycloserine than with a placebo.

METHODS

In a 4-week single-site double-blind randomized placebo-controlled trial, fifty adults with Major Depressive Disorder (MDD) (NCT03937596) were randomized to receive placebo or D-Cycloserine (100 mg) with daily intermittent theta-burst stimulation (iTBS) to the left dorsolateral prefrontal cortex (DLPFC). At baseline and after treatment, self-criticism was assessed using the Depressive Experiences Questionnaire as a secondary trial outcome and depressive symptoms were assessed using the clinician rated Montgomery Asberg Depression Rating scale (MADRS). Clinical response was defined as a ≥50 % decrease on the MADRS.

RESULTS

Self-criticism differentially predicted antidepressant effects when operationalized as both percent decrease on the MADRS and clinical response (≥50 % decrease), with a statistically significantly stronger association in the iTBS+D-Cycloserine group than the iTBS+Placebo condition. Self-criticism did not significantly change in either condition over the course of treatment.

CONCLUSIONS

Our data suggests that iTBS to the left DLPFC engages a circuit related to self-criticism. Higher levels of self-criticism predicted better response to iTBS with an adjuvant that enhances synaptic plasticity. This suggests that personality traits may be used to tailor non-invasive neurostimulation treatments.

rTMS Reduces Craving and Alcohol Use in Patients with Alcohol Use Disorder: Results of a Randomized, Sham-Controlled Clinical Trial

(1) Background: Current evidence-based treatments for alcohol use disorder (AUD) are moderately effective. Studies testing repetitive transcranial magnetic stimulation (rTMS) in AUD commonly apply a limited number of rTMS sessions with different rTMS settings, showing inconsistent effects on craving for alcohol. This study tested the efficacy of a robust rTMS protocol on craving and alcohol use. (2) Methods: In a single-blind randomized controlled trial in recently detoxified patients with AUD, ten days of high-frequency rTMS over the right dorsolateral prefrontal cortex on top of treatment as usual (n = 14) was compared with sham rTMS (n = 16). Outcome measures were alcohol craving and use over a follow-up period of one year. Analysis was performed by means of repeated measures multivariate analysis of variance. (3) Results: The results showed a main group-by-time interaction effect on craving (Wilks’ Λ = 0.348, F (12, 17) = 2.654, p = 0.032) and an effect of group on alcohol use (Wilk’s Λ = 0.44, F (6, 23) = 4.9, p = 0.002), with lower alcohol craving and use in the group with active rTMS compared to the control group. Differences in craving between groups were most prominent three months after treatment. At 12 months follow-up, there was no effect of rTMS on craving or abstinence. (4) Conclusions: This small-scale randomized controlled trial showed the efficacy of high-frequency rTMS over the right dlPFC diminished alcohol craving and use in recently detoxified patients with AUD during the first months after detoxification. These findings suggest that rTMS might be an effective add-on in treating patients with AUD and warrant replication in future large-scale studies.