Am J Psychiatry 2019 May 15;176(5):367-375. Epub 2019 Feb 15.
The Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto (Kaster, Knyahnytska, Daskalakis, Blumberger); the Department of Psychiatry (Kaster, Downar, Giacobbe, Kennedy, Daskalakis, Blumberger), the Institute of Medical Science (Downar, Giacobbe, Kennedy, Daskalakis, Blumberger), and the Dalla Lana School of Public Health (Thorpe), University of Toronto, Toronto; the MRI-Guided rTMS Clinic, Toronto Western Hospital, Toronto (Downar); the Krembil Research Institute, University Health Network, Toronto (Downar, Kennedy); the Department of Psychiatry, University of British Columbia, Vancouver (Vila-Rodriguez, Lam); the Non-Invasive Neurostimulation Therapies Laboratory, University of British Columbia, Vancouver (Vila-Rodriguez); the Shalvata Mental Health Center, Hod-Hasharon, Israel, and the Sackler School of Medicine, Tel Aviv University, Tel Aviv (Feffer); the Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo (Noda); the Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto (Giacobbe); and the Li Ka Shing Knowledge Institute, Saint Michael's Hospital, Toronto (Kennedy).
Objective: Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for refractory major depressive disorder, yet no studies have characterized trajectories of rTMS response. The aim of this study was to characterize response trajectories for patients with major depression undergoing left dorsolateral prefrontal cortex rTMS and to determine associated baseline clinical characteristics.
Methods: This was a secondary analysis of a randomized noninferiority trial (N=388) comparing conventional 10-Hz rTMS and intermittent theta burst stimulation (iTBS) rTMS. Participants were adult outpatients who had a primary diagnosis of major depressive disorder, had a score ≥18 on the 17-item Hamilton Depression Rating Scale (HAM-D), and did not respond to one to three adequate antidepressant trials. Treatment was either conventional 10-Hz rTMS or iTBS rTMS applied to the dorsolateral prefrontal cortex, 5 days/week over 4-6 weeks (20-30 sessions). Group-based trajectory modeling was applied to identify HAM-D response trajectories, and regression techniques were used to identify associated characteristics.
Results: Four trajectories were identified: nonresponse (N=43, 11%); rapid response (N=73, 19%); higher baseline symptoms, linear response (N=118, 30%); and lower baseline symptoms, linear response (N=154, 40%). Significant differences in response and remission rates between trajectories were detectable by week 1. There was no association between treatment protocol and response trajectory. Higher baseline scores on the HAM-D and the Quick Inventory of Depression Symptomatology-Self-Report (QIDS-SR) were associated with the nonresponse trajectory, and older age, lower QIDS-SR score, and lack of benzodiazepine use were associated with the rapid response trajectory.
Conclusions: Major depression shows distinct response trajectories to rTMS, which are associated with baseline clinical characteristics but not treatment protocol. These response trajectories with differential response to rTMS raise the possibility of developing individualized treatment protocols.