Scientists Identify What May Actually Drive Hair Pulling in Trichotillomania
Trichotillomania, or hair-pulling disorder, has been documented since ancient times, yet its causes remain only partly understood. Historically described as a troubling habit, modern psychiatry classifies it as a body-focused repetitive behavior that can cause visible hair loss and significant emotional distress.
Today, trichotillomania is estimated to affect about 1–2 percent of people in the United States. It occurs in both men and women, although more women seek treatment, and it often co-occurs with anxiety, depression, obsessive-compulsive disorder, post-traumatic stress disorder, and attention-deficit hyperactivity disorder.
Beyond simple stress relief theories
For years, many clinicians have explained hair pulling as a form of emotional regulation. According to this view, people pull their hair to reduce uncomfortable feelings such as anxiety, frustration, or inner tension, experiencing a short-lived sense of relief afterward.
However, research findings have not always supported this straightforward model. Many people with trichotillomania report pulling automatically while reading, watching television, studying, or scrolling on their phones, sometimes noticing the behavior only after hair has already been removed.
This gap between theory and lived experience prompted researchers at Heidelberg University Hospital in Germany to examine more closely what happens in real time. Their new study, published in Comprehensive Psychiatry, shifts attention from broad emotional states to the moment-to-moment urge to pull.
Tracking urges in everyday life
The research team followed 61 adults with trichotillomania over 10 days using ecological momentary assessment. Rather than relying on evening summaries, participants were repeatedly prompted throughout the day to record what they were feeling and whether they had pulled their hair.
Between 8 a.m. and 10 p.m., each participant received seven alerts on their smartphone. At every prompt, they rated their current emotional state, the intensity of their urge to pull, and whether a pulling episode had occurred since the previous check-in. Participants could also record pulling episodes as they happened.
Across the study period, this approach generated 2,557 real-time assessments and 702 recorded pulling episodes. The resulting dataset allowed the researchers to closely examine how urges, emotions, and behavior influenced one another from one moment to the next.
Urges, not feelings, drive behavior
The analysis showed that the strength of the urge to pull was the most powerful predictor of whether hair pulling actually occurred. When participants reported a stronger urge at a given moment, they were much more likely to report pulling during the same assessment.
Importantly, stronger urges at one time point also predicted pulling at the next prompt, suggesting that urges can build and persist over several hours. Previous pulling episodes increased the odds of additional episodes later in the day, pointing to a form of short-term behavioral momentum.
In contrast, emotional states were less reliable predictors of pulling itself. Negative emotions, including anxiety, anger, sadness, guilt, and nervousness, were associated with stronger urges, but they did not consistently predict actual hair pulling at the next assessment.
The surprising role of boredom
One internal state stood out across the data: boredom. Participants who reported feeling bored were more likely to experience strong urges to pull and were also more likely to report a pulling episode at the same or subsequent assessment.
Tiredness showed a related but slightly different pattern. Feeling tired was associated with stronger urges to pull, yet it did not directly predict whether pulling would occur, suggesting that low energy may increase vulnerability without necessarily leading to the behavior.
The findings suggest that trichotillomania may not be solely about escaping distress but could also represent a response to under-stimulation. Repetitive behaviors such as hair pulling may help some people regulate internal arousal when they feel bored, fatigued, or mentally under-engaged.
Rethinking treatment and future research
Based on these results, the authors argue that models focusing solely on emotional dysregulation are incomplete. Emotions appear to matter, but the key pathway may operate through the intensity of urges, which are shaped by boredom, energy levels, and ongoing behavioral patterns throughout the day.
Clinically, this may have implications for treatment. Strategies that increase awareness of urges, reduce idle time, and address chronic boredom or fatigue could complement existing cognitive-behavioral approaches, including habit reversal training and stimulus control techniques.
The study has notable limitations. The sample was relatively small, predominantly female, and consisted of people willing to complete an intensive 10-day protocol. Assessments were also up to four hours apart, meaning that very rapid changes in mood or urges may have been missed.
Still, the research adds an important layer of nuance to how experts understand trichotillomania. Instead of asking only which stressors trigger pulling, clinicians may need to focus more closely on what happens between the first flicker of an urge and the behavior itself, including environmental cues, sensory experiences, and levels of cognitive engagement.
As scientists continue to investigate these patterns, the hope is that more precise psychological and pharmacological treatments can be developed. For people living with trichotillomania, this could mean moving beyond shame and secrecy toward practical tools that address both emotional distress and the quieter moments of boredom that may contribute to the urge to pull.
