What Causes Trichotillomania? What Research Shows

If you pull your hair, or your child does, you’ve probably asked what causes trichotillomania. Is it something you did? Is it in the family? Does it mean something bad happened?

The short version is that there isn’t one cause. Trichotillomania (trich) seems to come from several things working together: the genes you’re born with, the way your brain forms and stops habits, and what pulling does for you in the moment. This guide explains what research has found about each one, how sure scientists are, and what it means for you and for parents.

Why do people pull their hair?

People pull because pulling does something for them. For many, it eases an uncomfortable feeling like tension, stress, anxiety or boredom. For others, pulling feels satisfying in itself. Either way, your brain notices the relief and learns to reach for it again.

Trichotillomania is a body-focused repetitive behaviour (BFRB), one of a group of conditions where people repeatedly pull, pick or bite at their own hair, skin or nails. Doctors class it with the obsessive-compulsive and related disorders. In one small study, most people with BFRBs said their pulling or picking was set off by anxiety, tension or boredom. People with trich also tend to find it harder than others to calm difficult feelings once they start.

Pulling can bring quick relief. That relief is what teaches the brain to reach for it again.

Each pull that brings relief makes the next one a little more likely, which is why pulling can feel so hard to stop. The loop doesn’t explain why some people fall into it and others don’t. That’s where genes and the brain come in.

Researchers describe two styles of pulling. Automatic pulling happens without you noticing, often while reading, scrolling or watching TV. Focused pulling is more intentional, usually to ease an urge or a feeling. Most people do both. Our guide to focused and automatic pulling explains how to tell which is which.

What causes trichotillomania? The main factors at a glance

Factor	What research shows	How sure are we?
Genes	Trich runs in families, and twin studies show a real genetic part. Many genes each add a little.	Fairly sure genes play a part. The specific genes aren’t known yet.
The brain	Scans show small differences in areas that build habits, stop movements and handle emotions.	Early evidence from small studies, mostly in adults.
Feelings and coping	Pulling often eases stress, tension or boredom, and that relief keeps it going.	Fairly consistent evidence that this keeps pulling going. Less clear if it starts it.
Stress	Stressful times often come just before pulling starts or gets worse.	Widely reported as a trigger, not a cause on its own.
Trauma	Some people with trich have been through trauma; many haven’t.	The link is weak and may be explained by low mood.
Parenting	No evidence that parenting causes trich.	Studies can’t separate cause from effect.

Is trichotillomania genetic?

Partly, yes. Trich runs in families, and studies of twins show that genes make a real difference to who develops it. But there’s no single gene that causes it, and most relatives of someone with trich don’t have it.

Family studies compare relatives of people with and without trich. A 2024 review of all the genetics research found that in one family study, about 6 in 100 close relatives of people with trich had it too, and none of the relatives in the comparison group did. The same families also had more obsessive-compulsive disorder (OCD), a condition where people have unwanted, repeated thoughts and feel driven to do things to ease them.

Trich can run in families, but most relatives of someone who pulls don’t develop it. Genes raise the chance; they don’t decide it.

Twin studies compare identical twins, who share all their genes, with non-identical twins, who share about half. If identical twins are more alike, genes are likely to be involved. Researchers use this to estimate heritability: how much of the difference between people in a group comes from their genes. For trich, one small twin study put it at 76%, and a much larger study of twins in the general population put it at about 32%. So genes seem to account for somewhere between a third and three-quarters of the risk, with the rest coming from other things, such as life experience.

Gene studies have looked for the genes involved. Some early work pointed to particular genes. In mice, switching off certain genes makes them groom themselves far too much. But the first scan of the whole human genome in people with trich, published in 2025, found no single gene with a clear effect. That study was small, about 100 people with trich, so larger ones are needed. What it did find is that people with trich tended to carry many small genetic differences linked to mental health conditions in general. A 2026 study of families pointed the same way, and suggested that trich shares some of its genetic roots with OCD. There’s more on how the two conditions relate in our guide to trich and OCD.

In plain terms: some people are born with a higher chance of developing trich. Genes load the dice. They don’t roll them.

What role does the brain play?

The brain seems to handle habits a little differently in people with trich. Brain scans have found small differences in areas that help build habits, put the brakes on movements, and manage emotions, and in the connections between them. That may make a repeated action easier to pick up and harder to switch off.

Most of these studies are small and were done with adults. They can’t tell us whether the brain differences came first or developed after years of pulling. And a difference on a scan isn’t damage. It’s closer to a different setting.

You may read that trich is caused by a chemical imbalance in the brain. The UK’s NHS lists this as one possible cause. It’s an idea researchers are still testing, not something that has been shown.

In practice, this means pulling isn’t a failure of willpower. The skills that help are ones that retrain those habit and braking systems, such as noticing the first move towards your hair and giving your hands something else to do.

Is it caused by stress or trauma?

Stress can trigger pulling, but it usually isn’t the cause. And trauma isn’t a general cause of trich, even though some people with trich have been through trauma.

Stress. Stressful times often come just before pulling starts or flares up. The Mayo Clinic, a large US medical centre, notes that very stressful events may trigger trich in some people. A useful way to think about it: stress is the spark, but it lands on someone who was already at risk. Many people go through great stress and never pull.

Trauma. Older studies found that most people with trich had been through a traumatic event, such as an assault or witnessing violence. A more carefully designed study, published in 2016, looked at 85 adults who came for treatment. About half had been through a traumatic event, fewer than earlier studies found. Those who had been through trauma didn’t score higher on the main hair-pulling scales. Where there was a link, it seemed to run through depression: trauma can lead to low mood, and some people then pull to cope with how they feel. The researchers concluded the link between trauma and trich is weak at best.

So having trich doesn’t mean something terrible must have happened to you. And if you have been through something painful, pulling may be one way you’ve coped with how it left you feeling. Both are understandable.

Why does it usually start in the early teens?

Trich most often begins between the ages of 10 and 13, and researchers have found this in many different countries. It can start earlier or later, but the early teens are the most common time.

Nobody knows exactly why. Hormone changes around puberty may play a part; the NHS lists them as one possible factor.

Very young children pulling their hair is often a different thing. The Mayo Clinic notes that mild hair pulling in babies usually goes away without treatment.

In childhood, boys and girls seem to be affected about equally. In adults, around four times as many women as men are diagnosed, though some of that gap may be because women are more likely to seek help.

Is it the parent’s fault?

No. There’s no evidence that parenting causes trichotillomania. If your child pulls, it isn’t because of something you did or didn’t do.

Two studies found that families of teenagers with trich reported more conflict and less support at home, and that parents, especially mothers, reported more stress, anxiety and low mood. But both studies measured families at a single moment. The authors of both said they couldn’t tell which came first. Living with a child who is distressed and struggling to stop can strain any family, and worried parents are bound to feel stressed.

What about genes? If trich runs in your family, you may have passed on some risk. That isn’t fault either. Nobody chooses their genes, and most children of parents with trich don’t develop it.

Where parents do make a real difference is in how they respond now. Staying calm, not telling your child off, and helping them feel less alone all make pulling easier to manage. Our guide on what to say to a child who pulls their hair has words that help. For a fuller picture, The Parent’s Guide to Trichotillomania is about understanding what your child is going through.

What doesn’t cause trichotillomania, and why does it matter?

Several common beliefs about trich are wrong, and they add to the shame.

It isn’t a bad habit. It’s a recognised condition with its own research and treatments.
It isn’t a lack of willpower. Genes and the brain’s habit systems are involved.
It isn’t attention-seeking. Many people with trich feel ashamed and hide it.
It isn’t self-harm. People pull for relief, soothing or satisfaction, not to hurt themselves, and trich is classed as a separate condition.
It isn’t caused by bad parenting. See the section above.

Knowing this matters because it changes what helps. If trich were about willpower, trying harder would work. It doesn’t, because pulling is a learned loop running on brain systems that are partly shaped by genes. What helps is working on the loop itself.

Habit Reversal Training (HRT) is a type of behavioural therapy that does this. It teaches you to notice when you’re about to pull and to do something else with your hands instead. Other approaches add ways to handle the feelings and urges that drive pulling, or to change the places and times where it happens. For an overview of every option and the evidence behind each, see our guide to trichotillomania treatment.

You didn’t choose this, and neither did your child. Our complete guide to trichotillomania covers the causes alongside everything else you might want to know.

When should I get help?

Get support if pulling is upsetting you or your child, taking up a lot of time, or getting in the way of school, work or relationships. You don’t need to wait until it’s "bad enough".

Many doctors and therapists have never worked with someone who pulls. Everyone in our directory has told us they understand trichotillomania and already help people who pull, in person or online. You can search the directory to find someone who understands hair pulling.

If you’re feeling very low or hopeless, please talk to someone today.

In an emergency, call 995 or go to your nearest emergency department.

Samaritans of Singapore (SOS) — 1767 (24h)
IMH Mental Health Helpline — 6389 2222

Questions people ask

Can you develop trichotillomania as an adult?

Yes. Most people start pulling in childhood or their early teens, but some start later in life, sometimes around a stressful time. The same things that help younger people, such as tracking when you pull and learning to ride out urges, help adults too.

Is trichotillomania a mental illness?

It’s a recognised mental health condition, listed in the DSM-5 among the obsessive-compulsive and related disorders. That doesn’t mean something is wrong with your character. It means pulling is a known pattern with its own research and treatments, and you don’t have to handle it alone.

Is trichotillomania more common in women?

In children, boys and girls seem to be affected about equally. In adults, around four times as many women as men are diagnosed. Part of that gap may be because women are more likely to seek help, so men who pull may be under-counted.

If I have trich, will my child get it?

Probably not. Trich does run in families, but in one family study about 6 in 100 close relatives of people with trich had it themselves. That means most close relatives don’t have it. Genes raise the chance a little; they don’t decide it.

Why did my pulling start after a stressful event?

Stressful times often come just before pulling starts or gets worse. Stress doesn’t create trich from nothing, but for someone already at risk it can be the moment pulling first becomes a way to cope. Noticing that link can help you plan for stressful times ahead.

Is hair pulling caused by anxiety?

Anxiety is one of the most common triggers, but it isn’t the cause for everyone. Many people also pull when bored or tense, or without noticing at all. Trich isn’t classed as an anxiety disorder, though the two often happen together.