Background: Neurocognitive dysfunction is an understudied and undertreated aspect of psychiatric research and treatment. There is emerging evidence to suggest that repetitive transcranial magnetic stimulation (rTMS) may possess neurocognition-enhancing capabilities.
Methods: This study examined the neurocognitive data from a randomized, double-blind, sham-controlled trial of an investigational 2-coil rTMS device in antidepressant treatment or treatment-intolerant major depressive disorder patients. This device has the potential to stimulate deeper areas of the brain than the Food and Drug Administration-approved TMS devices, which primarily stimulate cortical brain areas and may therefore have different neurocognitive adverse effects. Patients received 20 daily rTMS treatments (10-Hz stimulation; either active or sham) with coil centers positioned over the left dorsolateral prefrontal cortex and dorsomedial prefrontal cortex. Neurocognitive safety was evaluated at baseline and within 72 hours of final treatment session with a computerized battery assessing aspects of attention and memory in 84 participants.
Results: There were no observed negative neurocognitive effects of the 2-coil rTMS device. A significant effect of active rTMS was observed on the quality of episodic memory. There were no observed effects for attention or working memory. Baseline quality of episodic memory predicted depression treatment response and remission, in that lower baseline episodic memory was associated with greater likelihood of depression response/remission. This was observed in logistic regression analyses controlling for treatment and baseline depressive symptoms.
Conclusions: The 2-coil rTMS device is a cognitively safe treatment for treatment-resistant depression that may possess episodic memory-enhancing capabilities. Furthermore, baseline episodic memory may reflect an important predictor of subsequent depression treatment response/remission to rTMS.