A new case study provides initial evidence that transcranial direct current stimulation (tDCS) may be an effective treatment option for trichotillomania, also known as hair pulling disorder.
The study tested an intensified, repeated tDCS protocol targeting the supplementary motor area and dorsolateral prefrontal cortex in a 25-year-old woman with trichotillomania.
After 16 sessions over 20 days, the patient showed significant improvements in hair pulling symptoms as well as depression and anxiety.
While larger studies are needed, this case highlights the potential of tDCS as a novel therapy for this challenging condition.
What is Trichotillomania?
Trichotillomania is characterized by the irresistible urge to pull out one’s own hair, leading to noticeable hair loss.
Hair is most often pulled from the scalp, but can also be pulled from eyebrows, eyelashes, and other parts of the body.
Trichotillomania was previously classified as an impulse control disorder but was reclassified in DSM-5 as an obsessive-compulsive related disorder due to its similarities with OCD.
Trichotillomania affects 1-2% of people, with onset most often occurring in adolescence.
For many, it becomes a chronic condition.
Hair pulling serves as a way to relieve anxiety or tension, but ultimately causes distress and impairment.
Those with trichotillomania may go to great lengths to hide their hair loss.
Significant shame, embarrassment, and lowered self-esteem are common.
Current Treatment Limitations for Compulsive Hair Pulling
While behavioral therapies like habit reversal training are first-line treatments, many patients fail to respond adequately or relapse after initial improvement.
Selective serotonin reuptake inhibitors are sometimes used off-label, but have limited efficacy for trichotillomania symptoms.
Atypical antipsychotics like olanzapine have also been tried, but side effects may limit their usefulness.
There is a lack of FDA-approved medications for trichotillomania, and existing treatment options leave much to be desired.
Developing novel treatments with better efficacy and fewer side effects is an important goal.
Non-invasive brain stimulation like tDCS represents a promising approach.
The Potential of tDCS for Trichotillomania
Transcranial direct current stimulation (tDCS) is a form of neuromodulation that uses a constant, low current delivered through electrodes on the head.
It is thought to alter cortical excitability in target brain regions.
tDCS is safe, well-tolerated, and increasingly used for various psychiatric conditions.
tDCS has shown promise for improving OCD symptoms.
Trichotillomania shares overlap in the underlying neurobiology and behaviors like repetitive habits.
Targeting brain circuits involved in habit formation and inhibition like the supplementary motor area (SMA) may help treat trichotillomania as well.
The SMA is involved in preparation and inhibition of voluntary movements.
Hyperactivity in this region could contribute to impaired control over hair pulling. Cathodal tDCS, which decreases excitability, over the SMA may help treat trichotillomania by enhancing inhibitory control.
Prior work also suggests dorsolateral prefrontal cortex (DLPFC) abnormalities play a role in trichotillomania.
Anodal tDCS to the left DLPFC may help by modulating emotion regulation circuits.
However, tDCS had not yet been systematically studied for trichotillomania before this recent case report.
The Case Study: 25-Year-Old Female with 10 Years of Hair Pulling
Researchers from the University of Zanjan in Iran tested an intensive tDCS protocol in a 25-year-old married woman with a 10-year history of trichotillomania.
She had previously tried medications like antidepressants and antipsychotics, but still experienced worsening hair pulling.
The study design involved:
- 16 tDCS sessions over 20 days, with 2 sessions per day separated by a 20 minute break
- 20 minutes of 2mA tDCS per session
- Cathode electrode over SMA, anode over left DLPFC
- Assessments at baseline, end of treatment, and two follow-up visits
The participant tolerated the protocol well without any concerning side effects.
tDCS was associated with dramatic improvements in her trichotillomania symptoms.
What were the effects of tDCS on compulsive hair pulling?
The patient’s baseline scores indicated severe trichotillomania.
On the Massachusetts General Hospital Hair Pulling Scale (MGH-HPS), her initial score was 85.
Scores below 10 are considered remission, while scores above 21 indicate severe symptoms.
After the tDCS sessions, her MGH-HPS score reduced to 37, a 56% improvement.
Further improvement occurred during the follow-up period.
Six weeks after starting tDCS, her MGH-HPS score was 31, representing a 64% reduction from baseline.
The patient also rated her urges to pull hair on a visual analog scale. Her initial score was 75.
This decreased to 45 after tDCS and improved further to 35 at the 6 week follow-up, representing a 53% improvement.
In addition to improving trichotillomania symptoms, tDCS also reduced the patient’s depression and anxiety.
Baseline depression was in the severe range on the Beck Depression Inventory II.
Depression improved by 31% after tDCS and 34% at follow-up.
Anxiety scores decreased by 41% after tDCS and 52% at follow-up.
These results demonstrate clinically significant improvements across all outcome measures that were sustained well beyond the end of stimulation.
Significance and Limitations of this Case Report
This case study provides preliminary evidence that repeated tDCS targeting the SMA and DLPFC could be an effective new treatment approach for trichotillomania.
To the authors’ knowledge, it is the first application of tDCS for this condition.
However, there are important limitations to consider:
- As a case study, no control group was used for comparison. The results could reflect natural variation in symptoms over time rather than a real effect of tDCS.
- Further research with larger sample sizes, control groups, and randomized blinded designs is required to truly determine efficacy.
- It is unknown if the improvements were primarily due to SMA stimulation, DLPFC effects on mood, or synergistic effects between the two targets.
- Longer-term follow-up is needed to assess durability of tDCS benefits over months.
While promising, caution is warranted when interpreting a single case report.
Wider validation is needed before clinical application. This early data provides proof of concept that can inform future sham-controlled trials.
Mechanisms of tDCS for Trichotillomania (Hypotheses)
Assuming the observed benefits are borne out in larger trials, what are the potential mechanisms by which tDCS could improve trichotillomania?
The cathodal electrode over the SMA likely reduced cortical excitability in this key region.
Dampening hyperactivity in motor preparatory circuits could directly decrease urges and the tendency to engage in hair pulling behaviors.
Enhancing activity in the left DLPFC may also help by improving cognitive control and emotion regulation capacity.
The DLPFC is important for controlling impulses and modulating emotional responses.
Strengthening prefrontal cognitive control networks could make hair pulling urges easier to override.
Finally, depression and anxiety are common comorbidities and pull-related triggers in trichotillomania.
By reducing negative mood symptoms, tDCS may decrease an important source of hair pulling urges.
Multiple complementary neuromodulation effects across cortical-striatal-thalamic circuits could culminate in therapeutic benefits.
Future Research of Non-Invasive Neurostimulation for Trichotillomania
This initial case study sets the stage for more definitive controlled research on tDCS and trichotillomania.
Some future directions include:
- Larger sham-controlled trials to replicate results
- Compare tDCS to first-line treatments like habit reversal therapy
- Examine effects on actual hair regrowth over months
- Optimize parameters like electrode locations, session number, and duration
- Identify predictors of tDCS response
- Combine tDCS with psychotherapy or medications for additive benefits
- Compare tDCS to other neuromodulation approaches like repetitive TMS
- Assess the cost-effectiveness and feasibility of tDCS in real-world clinical settings
For now, tDCS should not be used clinically for trichotillomania outside of research trials.
But with further study, tDCS could one day be incorporated into treatment guidelines as a complementary approach to enhance outcomes.
This work lays the foundation for larger studies to evaluate the viability of tDCS as a much-needed therapeutic option.
Final Takeaways: tDCS for Trichotillomania
In summary, this case study provides initial evidence that repeated tDCS targeting the SMA and DLPFC may help treat trichotillomania symptoms.
Additional sham-controlled trials are warranted to confirm and extend these findings.
Non-invasive brain stimulation like tDCS represents a promising new direction for better treating this challenging hair pulling disorder.
This research sheds light on innovative neuromodulation strategies that could improve quality of life for sufferers of trichotillomania.
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