Repetitive transcranial magnetic stimulation for cognitive function in adults with bipolar disorder: A pilot study

Background: Cognitive deficits are prevalent in bipolar disorder and are a significant contributor to negative patient-reported outcomes. Herein we conducted a pilot study of repetitive transcranial magnetic stimulation (rTMS) to improve cognitive function in adults with bipolar disorder. Methods: The study was a triple-blinded, randomized, placebo-control trial. Participants (aged 18 to 60) with a diagnosis of DSM-5-defined bipolar disorder (I or II) were recruited and randomized (N=36) to receive either a sham treatment (n=20) or an active rTMS treatment (n=16). Patients completed the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) at baseline and 1-2 weeks after the rTMS intervention. Results: A significant group by time interaction was observed in the Hopkins Verbal Learning Test-Revised (HVLT-R), (F (1, 34) = 17.0, p < 0.001, partial eta 2 = 0.33). Post-hoc analysis revealed that although both groups did not significantly differ at baseline (p = 0.58), patients in the active rTMS group significantly improved following neurostimulation (p = 0.02) for HVLT-R. Moreover, within-subject analysis indicated that the active rTMS group significantly improved in score from pre-treatment to post-treatment (p < 0.001), while the sham group did not improve (p = 0.94) for HVLT-R. No significant differences were seen in the other cognitive measures. Limitations: The study was conducted in a small sample . Conclusion: This pilot study, which was intended to establish feasibility, suggests that rTMS may offer benefit in select domains of cognitive functioning in bipolar disorder. None of the measures across subdomains revealed a dyscognitive effect.