How TMS Reduces Anhedonia and Suicidal Thoughts in Treatment-Resistant Depression

Understanding Treatment-Resistant Depression (TRD)

Depression is one of the most common mental health conditions worldwide, but for about one in three patients with major depressive disorder (MDD), standard treatments like antidepressants and therapy aren’t enough. This condition, known as treatment-resistant depression (TRD), is especially challenging because it often comes with two particularly stubborn symptoms:

  • Anhedonia — the inability to feel pleasure or interest in activities.
  • Suicidal ideation (SI) — persistent thoughts about death or suicide.

These symptoms don’t always improve with traditional approaches, leaving patients and providers searching for new solutions.

TMS: A Promising Alternative

Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation therapy that targets circuits in the brain linked to mood regulation. By stimulating the dorsolateral prefrontal cortex (dlPFC), TMS has already shown success in improving depression. But researchers at the University of Minnesota Interventional Psychiatry Program wanted to explore something deeper: could TMS specifically reduce anhedonia and suicidal thoughts, and are these two symptoms linked?

The Study at a Glance

  • Who participated: 181 adults with TRD, all of whom had not improved with at least two antidepressant medications.
  • What they received: TMS treatments using either a Figure-8 coil or an H1-coil, both approved devices targeting the dlPFC.
  • How symptoms were measured: Standard depression rating scales (PHQ-9 and IDS-SR) tracked overall depression, anhedonia, and suicidal ideation before and after treatment.

Key Findings

  1. Overall Depression Improved:
    TMS significantly reduced total depression scores, with nearly 42% of patients showing a meaningful response on one measure.
  2. Anhedonia and Suicidal Thoughts Improved Too:
    • Both symptoms decreased substantially.
    • Effect sizes (a way to measure strength of change) were large: d = 1.03 for anhedonia and d = 0.88 for suicidal ideation.
  3. Anhedonia Predicted Suicidal Ideation:
    Perhaps the most important finding was that improvement in anhedonia predicted improvement in suicidal thoughts — even after accounting for other depression symptoms. This suggests that these two issues may share underlying brain pathways.
  4. Type of TMS Device Didn’t Matter:
    Both the Figure-8 and H1-coil produced similar results, showing that targeting the dlPFC broadly is effective.

Why This Matters

This study reinforces TMS as a powerful option for people with TRD who haven’t found relief from other treatments. Even more importantly, it suggests that anhedonia and suicidal ideation are deeply connected. By treating one, clinicians may indirectly help the other.

For patients struggling with a lack of joy and persistent suicidal thoughts, these results offer hope. It also gives researchers new directions: future studies may use brain imaging to confirm whether these symptoms share the same “circuit” in the brain, paving the way for even more precise and personalized TMS treatments.

Takeaway

If you or someone you know is battling treatment-resistant depression, TMS isn’t just another option for mood improvement — it may also directly address the crushing weight of anhedonia and suicidal thoughts. This makes it one of the most promising tools in the mental health field today.

📖 Citation (APA 7th ed.):
Sonmez, A. I., Webler, R., Krueger, A. M., Godoy-Henderson, C., Sullivan, C., Wilson, S., Olsen, S., Schmid, S., Herman, A., Widge, A., Peterson, C., Nahas, Z., & Albott, C. S. (2024). Effects of TMS on anhedonia and suicidal ideation in treatment-resistant depression: Outcomes from the University of Minnesota Interventional Psychiatry Program. Journal of Mood & Anxiety Disorders, 8, 100073. https://doi.org/10.1016/j.xjmad.2024.100073