Chronic caffeine consumption on clinical TMS outcomes: A naturalistic retrospective analysis

Health and behavioral factors likely influence repetitive transcranial magnetic stimulation (rTMS) effectiveness, though clear support is lacking. Since habitual caffeine use has been found to impair corticomotor plasticity, we hypothesized that clinical benefits may likewise be impaired. We performed a retrospective analysis (n = 179) from the McLean Hospital TMS Clinic to explore the effect of self-reported caffeine use on TMS clinical outcomes. Self-report depression and anxiety scales from caffeine users and non-users were compared with Wilcoxon-rank-sum test and response and remission rates with chi-square; Spearman's was used to correlate correlation caffeine quantity with degree of clinical change. Both groups experienced a significant reduction in depressive symptoms as expected. Contrary to our hypothesis, however, we found no differences between caffeine users and non-users in total symptom reduction or response and remission rates, nor did we find a relationship between caffeine quantity and clinical change. This naturalistic analysis suggests that chronic caffeine consumption does not influence treatment outcomes in clinical rTMS for depression.