The effect of once-daily vs. twice-daily intermittent theta burst stimulation on suicidal ideation in treatment-resistant depression.

Intermittent theta burst stimulation (iTBS) has demonstrated potential in reducing suicidal ideation (SI) in patients with depression, however, stimulation protocols vary greatly across studies. For this secondary analysis, data from a three-site double-blind, randomized and sham-controlled clinical trial was analyzed to investigate the efficacy of a once-daily versus twice-daily iTBS protocol in the treatment of SI in patients with treatment resistant depression. Secondarily we aimed to explore the associations among SI, anhedonia and quality of life (QOL) measures. The primary outcome for this analysis was SI, which was assessed by computing an average score from four suicidality items on separate depression scales. 158 participants who experienced some degree of SI at baseline were included in the analysis. After 10 days of treatment, 15 (18.3%) participants from the once-daily group and 19 (25%) from the twice-daily group achieved remission from SI which was defined as a SI score of 0. After 30 days of treatment the remission rates were 27 (32.9%) and 30 (39.5%), respectively. There were no significant differences in remission rates between the groups. Moderate correlations between change in SI and change in depressive symptoms were observed. In addition, correlations between change in SI, anhedonia and QOL were observed that remained significant after controlling for change in depressive symptoms. Achieving remission from SI appears to be at least partially correlated to the anti-depressant effect of iTBS. Further studies investigating optimal treatment protocols for the treatment of suicidality with different iTBS schedules are urgently needed. Trial registration Clinicaltrials.gov ID: NCT02729792 ( https://clinicaltrials.gov/ct2/show/NCT02729792 ).