The key finding
A systematic review published in 2024 analyzing 21 studies found that transcranial magnetic stimulation (TMS)—a treatment that uses magnetic pulses to stimulate specific brain regions—is linked to improvements in cognitive control among people with major depressive disorder (MDD). The most notable improvements appeared in inhibition (the ability to suppress unwanted thoughts or actions), attention, set shifting/flexibility (switching between mental tasks), and memory. However, the review also found that improvements in visuospatial function, recognition, executive function, phonemic fluency, and information processing speed were less consistently observed across studies.
What the study looked like
This was a systematic review that synthesized findings from 21 existing studies examining TMS effects on cognitive function in patients with major depressive disorder. The reviewed studies included participants who underwent various TMS protocols, including repetitive TMS (rTMS) and theta-burst stimulation—different methods of delivering magnetic pulses to the brain. The primary focus was identifying changes in cognitive control processes following TMS treatment. Participants in these studies were patients diagnosed with MDD who received TMS targeting the prefrontal cortex, the brain region responsible for cognitive control functions like planning, decision-making, and managing thoughts and actions. The review did not specify exact participant numbers or age ranges across all studies, as it compiled findings from multiple independent investigations with varying designs and durations.
Why researchers think this happened
Major depressive disorder affects not only emotional regulation but also cognitive processes controlled by the prefrontal cortex. The researchers suggest that TMS works by directly stimulating underactive regions of the prefrontal cortex, potentially normalizing brain activity patterns disrupted by depression. Since cognitive control—the ability to use information about goals and motivations to guide thoughts and actions—relies heavily on prefrontal cortex function, targeted magnetic stimulation may help restore these capabilities. The review notes that psychotropic medications don’t work for all patients with MDD, making alternative treatments like TMS particularly valuable. Previous research has shown mixed results on TMS cognitive effects, which the authors attribute to variations in stimulation protocols, parameters, and target locations. The predominantly positive findings for attention, inhibition, and flexibility suggest these cognitive domains may be particularly responsive to prefrontal cortex stimulation.
How to read this carefully
This review reveals important limitations that readers should consider. The authors explicitly note that previous studies provided “mixed results,” with some finding significant improvement while others did not. This inconsistency suggests that TMS doesn’t work uniformly for everyone or under all conditions. Additionally, as a systematic review rather than a new clinical trial, this study synthesizes existing research but doesn’t generate new data. The lack of clarity about “specific TMS protocols and stimulation parameters” means we don’t yet know which exact treatment approaches work best. The review also found that some cognitive domains showed “fewer significant improvements,” indicating TMS effects aren’t universal across all thinking skills. Readers should understand these are associations between TMS treatment and cognitive improvements, not definitive proof of causation, and individual results may vary considerably.
What this means for everyday life
For people living with depression who experience “brain fog,” difficulty concentrating, or trouble managing daily tasks, this review offers cautious optimism about TMS as a potential treatment option beyond medication. If you or someone you know struggles with depression-related cognitive difficulties—like forgetting appointments, having trouble focusing at work, or finding it hard to switch between tasks—it might be worth discussing TMS with a mental health professional, particularly if medications haven’t been fully effective. The findings suggest that improvements might be most noticeable in areas like attention and mental flexibility rather than all cognitive functions equally. However, given that researchers still need to clarify which specific protocols work best, TMS should be considered an emerging option rather than a guaranteed solution, and decisions should be made in consultation with qualified healthcare providers who can assess individual circumstances.