How to Schedule rTMS for Treatment-Resistant Depression Any Time of Year
How should clinicians use seasonal daylight information when scheduling a full rTMS course for treatment-resistant depression?
Patients with treatment-resistant depression often need timely access to rTMS, and clinicians may wonder whether starting treatment in winter or summer could affect the chance of response. This study addresses whether average daylight duration during a standardized rTMS course was associated with response or remission in a highly treatment-resistant sample.
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Confirm that the patient matches the studied treatment-resistant population
Apply this workflow most directly to patients with major depressive disorder who have failed 4 or more antidepressant medications from at least 2 different classes and have also had unsuccessful psychotherapy. That is the population studied, so the finding about daylight duration is best used in similarly treatment-resistant patients.
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Use the standardized full-course rTMS protocol rather than altering timing for season
In the study, rTMS was delivered with an H1-coil to the left dorsolateral prefrontal cortex using the FDA-approved protocol: 18-Hz stimulation in 2-second trains with 20 seconds between trains, 55 trains total, 1,980 pulses over 20 minutes, at 120% of motor threshold. Treatment was delivered daily for 6 weeks, followed by taper sessions at week 7 with 3 sessions, week 8 with 2 sessions, and week 9 with 1 session before discontinuation.
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Do not delay treatment to wait for longer daylight months
The median average daylight duration was 704 minutes in responders, 701 minutes in remitters, and 718 minutes in nonresponders, and no statistical difference was found between responder and nonresponder groups or between remitter and nonresponder groups. Based on this study, average daylight duration during the treatment course did not distinguish who responded or remitted.
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Track outcomes with standard depression scales
Assess baseline severity before starting rTMS and repeat assessment at the end of treatment using PHQ-9 and HDRS, as done in the study. Define response as a 50% or greater decrease in PHQ-9 or HDRS score, define remission as PHQ-9 less than 5 or HDRS less than 7, and classify patients with less than 50% improvement as nonresponders.
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Counsel patients that season alone should not guide start date
When patients ask whether they should wait for a different time of year, explain that this study did not find a significant association between average daylight duration and rTMS response or remission. You can tell patients that, in this sample, treatment efficacy did not appear to depend on whether the course occurred during periods with shorter or longer daylight.
Clinical Considerations
- This was a single-site study using one rTMS protocol, so the finding should be applied most directly to similar treatment settings.
- Potential confounders such as depression severity, concomitant medications, stress levels, and other seasonal environmental factors were not accounted for.
- Average daylight minutes may not capture the most relevant aspects of light exposure, including timing of exposure and intensity.
- Only patients who completed the full course were analyzed, so the finding does not address dropouts or early discontinuation.
Bottom Line
For patients completing this standardized rTMS course for highly treatment-resistant depression, average daylight duration should not be used to delay or time treatment by season.
