High frequency repetitive transcranial magnetic stimulation treatment for major depression: Dissociated effects on psychopathology and neurocognition.

OBJECTIVES: This open-label pilot study explored the effects of a course of accelerated high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) on two neurocognitive domains (decision-making and impulse control) in patients with major depressive disorder (MDD). METHODS: Participants with MDD and a treatment resistant major depressive episode (n=24) underwent twice-daily HF-rTMS targeted at the left dorsolateral prefrontal cortex (lDLPFC) over two weeks. Psychopathology was assessed by clinician-administered and self-reported measures of depression and anxiety; decision-making was assessed by the Iowa Gambling Task, the Balloon Analog Risk Task and the Game of Dice Task; impulse control was assessed by the Stroop Color-Word Task, the Continuous Performance Task and the Stop-Signal Task. RESULTS: Depression and anxiety scores significantly improved from pre-post HF-rTMS treatment. However, none of the decision-making or impulse control variables of interest changed significantly from pre-post HF-rTMS. Moreover, there was no correlation between changes in psychopathological symptoms and in neurocognition. LIMITATIONS: This is a moderately sized open label trial, and the confounds of ongoing psychotropics and illness chronicity can not be excluded in this treatment resistant sample. CONCLUSIONS: There is dissociation between acute symptomatic benefit after a course of accelerated HF-rTMS applied to the lDLPFC in treatment resistant MDD and performance on tests of decision making and impulse control. Though rTMS appears cognitively safe, additional research is warranted to understand this potential dissociation and its putative clinical implications.

Efficacy of theta burst stimulation (TBS) for major depression: An exploratory meta-analysis of randomized and sham-controlled trials.

Theta burst stimulation (TBS) has been proposed as a novel treatment for major depression (MD). However, randomized and sham-controlled trials (RCTs) published to date have yielded heterogeneous clinical results and we have thus carried out the present systematic review and exploratory meta-analysis of RCTs to evaluate this issue. We searched the literature for RCTs on TBS for MD from January 2001 through September 2016 using MEDLINE, EMBASE, PsycINFO, and CENTRAL. We then performed a random-effects meta-analysis with the main outcome measures including pre-post score changes in the Hamilton Depression Rating Scale (HAM-D) as well as rates of response, remission and dropout. Data were obtained from 5 RCTs, totalling 221 subjects with MD. The pooled Hedges' g for pre-post change in HAM-D scores was 1.0 (p = 0.003), indicating a significant and large-sized difference in outcome favouring active TBS. Furthermore, active TBS was associated with significantly higher response rates when compared to sham TBS (35.6% vs. 17.5%, respectively; p = 0.005), although the groups did not differ in terms of rates of remission (18.6% vs. 10.7%, respectively; p = 0.1) and dropout (4.2% vs. 7.8%, respectively; p = 0.5). Finally, subgroup analyses indicated that bilateral TBS and unilateral intermittent TBS seem to be the most promising protocols. In conclusion, although TBS is a promising novel therapeutic intervention for MD, future studies should identify more clinically-relevant stimulation parameters as well as neurobiological predictors of treatment outcome, and include larger sample sizes, active comparators and longer follow-up periods.