A Multisite, 6-Month, Open-Label Study of Maintenance Transcranial Magnetic Stimulation for Adolescents with Treatment-Resistant Depression

<b><i>Introduction:</i></b> Transcranial magnetic stimulation (TMS) is a promising intervention for adolescents with treatment-resistant depression (TRD). However, the durability of TMS-related improvement in adolescents is unclear. This 6-month study followed adolescents with TRD who had responded to TMS and provided TMS retreatment for adolescents with a partial relapse. <b><i>Methods:</i></b> The study enrolled adolescents (12-21 years) with TRD who had at least a partial response to sham or active TMS in a randomized controlled trial. Partial response was defined as ≥25% reduction of Hamilton Depression Rating Scale-24 (HAMD24). Participants with a partial relapse (≥1 point increase in Clinical Global Impression-Severity) received retreatment with daily 10 Hz TMS sessions until depressive symptom severity returned to the baseline score or after 30 TMS treatments. <b><i>Results:</i></b> There were 84 eligible participants, 66 were enrolled, and 41 completed the 6-month study. Twenty-eight participants (42%) were retreated with TMS. TMS retreatment courses had a mean of 22 sessions. At the 6-month follow-up, the complete sample exhibited reduced depressive symptoms (mean HAMD24 of 5.24) compared with baseline at entry into follow-up (mean HAMD24 of 8.21). Baseline depressive symptom severity was positively correlated with the risk of partial relapse, while the number of previous TMS interventions showed no correlation with the risk of partial relapse. TMS was well tolerated. <b><i>Conclusions:</i></b> This is the largest, long-term follow-up study with TMS retreatment for adolescents with TRD. These findings demonstrate the feasibility and clinical effects of a TMS retreatment protocol for adolescents with TRD, following a standard course of acute TMS.