The Future of PMDD Treatment: tDCS, Brain Stimulation & the Nettle Device

PMDD
Written By Georgina Standen

How tDCS Works: Changing the Brain’s Response to Hormonal Fluctuations

In PMDD we now understand that the problem isn’t simply “too many hormones” or “low hormones” but rather how the brain reacts to normal hormone changes. The mood swings, irritability and anxiety that characterise PMDD are thought to arise because areas of the brain (particularly the prefrontal cortex and motor/pain-processing regions) respond abnormally when levels of progesterone metabolites (such as allopregnanolone) rise and fall.

Transcranial direct current stimulation (tDCS) is a technique where a low-level electrical current is applied via electrodes to certain scalp regions, altering cortical excitability and connectivity. In simple terms: it gently “nudges” the brain circuits involved in mood regulation, pain perception and emotional control. Studies in depression, anxiety and chronic pain have shown that tDCS over the dorsolateral prefrontal cortex (DLPFC) or motor cortex (M1) can reduce symptoms of mood disturbance and pain. For example, a wearable home-based tDCS device aimed at women’s menstrual health demonstrated good usability and safe self-administration.

In the context of PMDD, tDCS offers a way to stabilise the neural circuits that over-react to hormone-linked changes rather than suppress the hormones themselves. Because it doesn’t rely on altering hormone levels, it holds promise for women who cannot tolerate hormonal treatments or antidepressants, or for whom those treatments have been ineffective.

The Nettle Device: What It Is & What the Trial Is For

The Nettle device, developed by Samphire Neuroscience, is a CE-marked Class IIa medical wearable that uses tDCS for menstrual health (pain and low mood). It is designed to be worn at home, controlled by a mobile app, and targets both the motor cortex (for pain) and the prefrontal cortex (for mood regulation).

In February 2025, it was announced that the SBRI Healthcare competition awarded a grant of £88,811 to the partnership of Queen Mary University of London and Samphire Neuroscience for the project titled “Validation of a Non-Invasive Brain Stimulation Device (Nettle) to Manage Symptoms of Premenstrual Dysphoric Disorder”.

This study is being led by Dr Paul Faulkner at Queen Mary and includes two primary objectives:

  1. To establish whether the Nettle device used at home (in the luteal phase or pre-period) can reduce the physical (pain) and mental (low mood, irritability) symptoms of PMDD.

  2. To investigate how it could be integrated into NHS care pathways, via round-table consultations with academics, clinicians and commissioners, preparing for eventual wider use.

To date the device has promising preliminary data for pain+mood in PMS/dysmenorrhea. One modelling/pilot study of the “home-based self-administered tDCS” device co-developed by Samphire showed very good usability and feasibility in women with menstrual pain and mood symptoms.

But importantly, no large published RCT yet confirms clinical efficacy in PMDD specifically. This UK trial is a key step toward that evidence.

Why It’s Significant: What This Could Mean for PMDD Care

  • Non-hormonal, drug-free option: Many women with PMDD cannot tolerate hormonal suppression, SSRIs or other medications due to side-effects or contraindications. A wearable tDCS device offers an alternative route.

  • Home-use, user-controlled: Because Nettle is wearable and app-controlled, it fits more easily into real life compared to hospital-based treatments or repeated injections. Early usability work found high user satisfaction.

  • Targeted mood + pain relief: By combining brain regions for both emotional regulation and pain sensitivity, this approach acknowledges how intertwined the mood and physical symptoms of PMDD are.

  • UK specific pathway: The emphasis on integrating into NHS care means that if the trial succeeds, it may become a reimbursable option in the UK, not just a consumer gadget.

Current Evidence: Where We Are & What We Still Need

What we know so far:

  • tDCS over the DLPFC/M1 has been studied in primary dysmenorrhea (period pain) and mood/anxiety symptoms, with improvements in pain and mood in small studies.

  • The Nettle device has demonstrated usability, home-self administration, and feasibility of sham-controlled set-ups.

  • The UK trial funded by SBRI is underway (or beginning) to target PMDD specifically.

What’s missing:

  • Large scale randomized controlled trials (RCTs) in women with diagnosed PMDD showing long-term symptom reduction, mood improvement, quality-of-life benefit.

  • Clear protocol data on optimal stimulation parameters (timing in cycle, duration, electrode montage) for PMDD.

  • Long-term safety and durability of effect (e.g., do benefits last across many cycles?).

  • Comparative data vs standard treatments (SSRIs/hormones) and cost-effectiveness for NHS adoption.

The forthcoming Queen Mary/Samphire trial aims to fill many of these gaps.

What’s Next in Research & Clinical Pathways

Over the coming years, key focuses will be:

  • Finalising the results of the UK validation study and publishing peer-reviewed data.

  • Deriving best practice protocols for home-use tDCS in PMDD (how many sessions, when in cycle, for how long).

  • Exploring biomarkers or neuroimaging to identify who is most likely to respond — critical for personalising treatment.

  • NHS pathway development: cost-benefit, clinician training, integration into women’s mental health/menstrual services.

  • Potential combination therapies: e.g., tDCS + CBT + hormone therapy for women with persistent symptoms.

At Sirona Health Ltd, we’re tracking this research closely, and as soon as robust UK-based evidence emerges, I will be able to offer advice about how this technology might fit into a personalised treatment plan.

FAQ

  • tDCS (transcranial direct current stimulation) uses low-level electrical current via scalp electrodes to modulate brain activity. It is non-invasive, typically well-tolerated, and early studies show good safety for home use in women’s health settings.

  • Not yet for PMDD. Although Nettle is CE-marked for menstrual pain/mood symptoms, its specific use in PMDD is still under clinical validation. The results of the UK trial will determine whether it becomes widely available via NHS or private care in the UK

  • Currently, treatments include SSRIs, hormonal suppression (e.g., combined pill, GnRH analogues), and non-pharmacological support. tDCS offers a new mechanism: modulating how the brain responds to hormonal changes rather than suppressing hormones or altering serotonin alone. It may be a future alternative or adjunct.

  • The trial will assess whether at-home use of Nettle in women diagnosed with PMDD can reduce both physical (pain, cramping) and mental (mood swings, anxiety, irritability) symptoms. It will also examine how to integrate such a device into NHS care pathways.

  • No – if you’re experiencing PMDD symptoms now, you should discuss existing evidence-based treatments (SSRIs, hormonal options, lifestyle support) with your clinician. The emerging tDCS approach is exciting, but currently experimental for PMDD in the UK.