Types of Hair Pulling & Skin Picking

Trichotillomania is considered a relatively rare disorder even though some studies indicate that a lifetime prevalence may be as high as 2 – 5%! However, the fact that it’s considered to be rare means that funding for research on this specific condition is often limited compared to more prevalent disorders. It’s because of this, we often have more questions than answers and we have to rely on clinical experience to extrapolate theories. Of course, as a practicing therapist I value clinical experience, it’s just that I would very much appreciate a larger pool of experiences and perspectives that more studies would bring.

Here is an example of how research can help us understand the experience of hair pulling. The types of hair pulling that I will write here about come from a study published in 2021 in CNS Spectrums called Neurobiology of subtypes of trichotillomania and skin picking disorder. The study has multiple co-authors, the team being led by a well-known name in our community, Dr. Jon E. Grant.

Even though BFRBs and OCD are not the same thing, we often draw parallels and rightfully so, some similarities do exist. Recent research has shown that different types of OCD may have specific neurobiological correlates. In other words, different types of OCD will engage different parts of our brains in charge of different psycho-biological processes. Having more information about this could help us customize treatments better and create better hypotheses about what happens to our clients. As always, the more information we have, the better we’re able to find some that apply to the people we work with.

As this study’s authors aptly note, to even contemplate researching neurobiological differences, we have to have something to differentiate – we have to see if there are different types of picking and pulling. This is the question that the study set to answer and I’m here to summarize its findings for you.

The following 3 types of hair pulling were identified:

1.      Sensory-sensitive hair pulling, characterized by low and infrequent urges to pull, but highly focused pulling when it does occur.

2.      Low awareness pulling, characterized by automatic pulling due to emotional triggers.

3.      Impulsive/perfectionist pulling, characterized by – you guessed it! – perfectionism and a tendency to use pulling to control unpleasant feelings.

2 subtypes of skin picking were identified:

1.      Emotional/reward picking where a person experiences frequent and intense urges often driven by intense and negative emotions.

2.      Functional picking, a subtype where urges are low, picking mild and distress minimal, although a person still recognizes they have a problem.

What category are you in? If you’re just getting started with your healing journey, it might be a good beginning to categorize yourself. Keep in mind that people are not statistics and that it may not be easy to fit into one group only, and in addition, we know that types of picking and pulling change over the years. In fact, sometimes people start with one BFRB and then abandon it for another at some point in life. Just now in the club, at least two members come to my mind that intermittently struggle with hair pulling and skin picking. All that is to say that you don’t need to fit a box 100% because the box is not custom made.

Neurobiology aside, I think it might be useful to know “your type” if nothing else then because it may help you pave your path forward. There are things that work for everyone – habit reversal training, stimulus control, some emotional regulation techniques, but if your picking or pulling fall into a category more precisely, you can consider some practical techniques. If your picking is related to emotional regulation, then there are ways to learn that. I used to give a whole course on the subject. If it’s related to perfectionism – here’s a topic to address in therapy. If you’re prone to trance-like states and extremely focused pulling like sensory-sensitive pullers, then your focus is supposed to be further exploration of how sensory stimulation works for you, etc.

This study didn’t provide any definitive proof that there is neurobiological specificity for all identified subtypes, but the following finding gives us hope that researchers will choose to continue their undertaking:

First, low awareness hair pullers demonstrated increased cortical volume in the lateral occipital lobe. Low awareness hair pullers appear to be the most common subtype of TTM and are best characterized as having more automatic hair pulling, and more pulling due to emotional triggers. In addition to visual perception, the lateral occipital cortex is involved in touch- and proprioception-related sensory activation. The other key finding was that our data demonstrate that impulsive/perfectionist hair pullers showed relatively decreased volume near the lingual gyrus of the inferior occipital–parietal lobe. (p.100 - 101)

Just in the rare case that you don’t routinely say things like occipital cortex, let’s provide a brief translation. Lateral occipital lobe helps process visual stimuli, but it’s also involved in some more specific forms of object recognition: recognizing some objects that you touch, and proprioception which is just a fancy way of saying the awareness of how your body moves.  The lingual gyrus has to do with processing visual, motion-related memories. Since this study found a decrease in cortical volume in these areas, it’s possible to conclude that this is a result (or a cause – hard to tell) of the fact that there’s very little awareness of pulling.

This is where we see that more studies are needed – will someone please give funding to these people!

If you are intrigued by this but don’t know what to make of it, we’re in it together! It’s not possible to say if cortical thickness is a consequence of the fact that there’s no awareness and therefore no activation of that area, or that low awareness comes from the fact that the area is morphologically the way it is. As always, however, I will argue that this doesn’t matter as much, since we know that our brains are plastic, with persistent effort it is possible to rewire it at least to an extent. That alone tells us that there’s no need to reach any catastrophic “my brain is bad” conclusions!

Here's what the authors have to say:

The lack of structural differences in these other subtypes leads to several possible explanations: perhaps these subtypes are less meaningful biologically. In fact, there was some suggestion based on the clinical phenotyping data that perhaps the subtypes of skin picking were actually reflective of symptom severity differences. If so, then neuroimaging of structural biology may be less useful in understanding the picking subtypes. Another explanation is that certain subtypes may have more subtle biological differences and thereby require a larger sample or a different imaging modality. (p. 101).

Not that any of the authors would care, but I do appreciate the subtle thinking here. BFRBs are not one thing and different people are – well, obviously – different people. Considering neurobiology may not yield useful information for everyone, while for some people or patterns it may be more relevant. In other words, this is not a one size fits all kind of a situation. It is, quite possibly, a beginning of a very interesting line of research that will help us craft more efficient psychotherapeutic strategies.