This week features a study that reveals that seasonal daylight exposure has no measurable effect on rTMS outcomes — alongside reassuring news about unwanted intrusive thoughts.
rTMS Works Year-Round for Treatment-Resistant Depression
A new retrospective study suggests that seasonal daylight exposure doesn’t influence how well patients with treatment-resistant depression respond to repetitive transcranial magnetic stimulation (rTMS). What the researchers discovered could streamline year-round treatment planning for clinics and patients alike.
The study appears this week in the Primary Care Companion of CNS Disorders.
Researchers looked at more than 150 adults with treatment-resistant depression who completed a full course of rTMS at a single U.S. medical center between 2018 and 2025. Every participant had failed at least four antidepressant trials across multiple drug classes. And none of them had responded to psychotherapy. Researchers assessed depression severity before and after treatment using the PHQ-9 and Hamilton Depression Rating Scale.
To test whether natural light exposure might influence treatment response, the researchers calculated the average daily daylight duration during each patient’s rTMS course using U.S. Naval Observatory data. The study’s authors classified patients as either responders, remitters, or nonresponders – based on standard symptom-reduction thresholds.
The results showed no meaningful differences in daylight exposure across outcome groups. Median average daylight duration remained between 11.5 and 12 hours for responders, remitters, and nonresponders alike. Simply put, statistical testing revealed no link between daylight duration and either response or remission.
What the researchers found is notable given the long-recognized links between light exposure, circadian rhythms, and mood. It also arrives at a time of growing interest in combining rTMS with other interventions, such as bright light therapy.
According to the authors, the results suggest that rTMS efficacy is stable across seasons, easing concerns that shorter winter days might act as a drag on treatment.
IN OTHER PSYCHIATRY AND NEUROLOGY NEWS
- New research in The Journal of Clinical Psychiatry found that while nearly 1 in 10 new birthing parents experience unwanted intrusive thoughts about sexually harming their infant, these thoughts don’t come with any increased risk.
- A PCC case study looks at a case of periodic catatonia in a 30-year-old man with autism spectrum disorder, with no other identifiable psychiatric or neurological comorbidities.
- Another JCP paper reveals that nearly 60% of U.S. veterans with PTSD meet criteria for the dissociative subtype.
- A PCC clinical review walks clinicians through how to recognize impulsivity as a symptom – not a diagnosis.
- And, finally, a sweeping new estimate suggests that U.S. schizophrenia costs totaled nearly $367 billion in 2024.
