Trich: Just a Habit or Motor Inhibition impairment?

I've been reading lots of academic articles about trich for awhile. In academic writing, the text can become very technical and heavy. So, I thought I might share some of my own thoughts on the interesting ideas brought up in the science of trichotillomania. 

Take a look at this article; Motor Inhibition and Cognitive Flexibility in Obsessive-Compulsive Disorder and Trichotillomania

They tested one trich group, and one OCD group against "healthy comparison subjects" on the computerized Stop-Signal Task, "subjects respond rapidly to left- or right-facing arrows on a computer screen with corresponding motor responses and attempt to inhibit responses when an auditory “stop signal” sounds. With a tracking algorithm, this task estimates the time taken to internally suppress prepotent motor responses (stop-signal reaction time)." 


This study provides data that there is a statistically significant difference between you (person with trich) being able to easily stop a task and someone without trich being able to stop doing the task in the study. How much worse were people with trich at stopping than the healthy comparison group?

The Trichotillomania group versus healthy comparison group: p<0.001. This is a small p value and we can reject the idea that the groups are the same. There is less than a 0.1% probability of a "false positive" or in other words extremely unlikely chance the trich people are the same as the healthy comparisons. In short, we are different! 

One of the interesting conclusions they drew: "Impairment of motor inhibition correlated significantly with symptom severity in trichotillomania." This suggest the more you pull hair out, the more you would perform worse at the test stop task. This makes sense intuitively as the worse you are at stopping, the more you pull because.... you just aren't good at stopping! Duh! At my worst, I felt like I couldn't bring my hand down. I felt like my hands were making the calls. So reading this study makes me feel like I wasn't just having "behavioral" problems that I had complete power to stop this whole time.  "Symptom severity in trichotillomania (Massachusetts General Hospital Hairpulling Scale scores) correlated significantly with stop-signal reaction times (r=0.564, p<0.02)". Again, this is a small p value showing that the worse the trich is, the worse the person was at the test stop task. 

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Maybe trich is simply a habit for others. Or maybe a habit is actually a type of motor inhibition impairment? Maybe what starts off as a habit, can transition into the involuntary area. When it crosses that line, perhaps it becomes more of a motor inhibition impairment and that's why it can be so hard to stop. 



Emily Kight