Review: "Tourette's syndrome, trichotillomania, and obsessive–compulsive disorder: How closely are they related?"

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I’d like to look at a Review from 2009 titled: “Tourette's syndrome, trichotillomania, and obsessive–compulsive disorder: How closely are they related?”. The link is here. Though if you can’t find access through a library you may be limited. A review is different from research because a review is written by a researcher who is referencing dozens or more studies to make generalizations. So they typically tend to be “newbie” friendly. It’s compiling conclusions of dozens of studies to tell us something from each that make a case for or against an idea.

The question of whether Tourette's syndrome (TS) and trichotillomania (TTM) are best conceptualized as obsessive–compulsive spectrum disorders has been raised by family studies on the close relationship between TS and obsessive–compulsive disorder (OCD). These disorders are characterized by repetitive behaviors and may have a number of phenomenological intersections as depicted in Fig. 1

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Figure 1. Obsessive–compulsive disorderTourette syndrome and trichotillomania. Legend: A—automatic trichotillomania; B—tic-like compulsion, complex tic (“compulsion-like” tic) and sensory phenomena; C—focused trichotillomania or hair focused obsessions or compulsions (“grooming-like” obsessive–compulsive symptoms) and sensory phenomena; D—complex repetitive behavior disorder.

I think this picture is nice because it demonstrates the subtypes hair pullers in relation to similarities to tics and OCD. I find myself appearing more like “B” where I have a compulsion like tic and sensory phenomena. That is not to say I am not on a “gradient” on don’t have features of “A” (automatic) or “C” "(Hair focused obsession pulling) or “D” (complex repetitive behavior disorder). Probably some parts of the day I am in “C” phase and other times, in “A” phase or in “D”.

So the researchers/readers might benefit from adding a color gradient to this idea. It would be neat if a motion tracking company like habit aware could team up with other type of pullers (non-automatic) to see if their technology actually can categorize these phases and get long term data. You could introduce new therapeutics and see from the tracking, how it impacts their TTM.

Anyway, might be nice if we had some clear definitions of what the researchers meant;

“Tourette's syndrome and OCD

2.1. Phenomenology

The main phenomenological differences between TS and OCD are presented in Table 1. In OCD, compulsions are typically performed in response to obsessive thoughts, images, or impulses. In contrast, in TS tics are not commonly preceded by obsessions. In addition, tics are sometimes performed involuntarily, whereas compulsions are always performed intentionally. Tics that are performed voluntarily and compulsions not preceded by obsessions represent an area of overlap between OCD and TS.” (So the area B-D) on figure 1.

The Tourette's Syndrome Classification Study Group (1993) describes tics as an “involuntary” (i.e., completely unintentional) response to either an urge or an unpleasant sensation (i.e., sensory phenomena), perceived as “voluntary”. Nevertheless, as indicated above, there are areas of overlap between complex motor tics and compulsions. For instance, repetitive behaviors such as touching or eye blinking may result from a need to relieve an urge or an unpleasant sensation, or to neutralize a superstitious fear.”

The term “intentional repetitive behavior” may have the advantage of encompassing various presentations of stereotyped repetitive behaviors reported in TS and OCD patients (as well as a number of other disorders, such as trichotillomania and stereotypic movement disorder), while at the same time allowing a clear differentiation from unintentional or involuntary tic phenomena (e.g., simple tics) (Miguel et al., 1995). The intentional repetitive behaviors of both TS and OCD can be conceptualized as responses to unpleasant internal cues.

So to summarize this, tourette’s is distinct in that the tic movement is described as “involuntary” but they do see overlapping, its not clear if tourette’s may also take a more intentional form or if that is distinct from TS and would be an OCD tic instead. If the tics is on the intentional side, it can be due to unpleasant internal cues. Not enough detail for my taste on what these “cues” mean exactly.

Moving on;

“2.1.2. OCD with tics

On a theoretical continuum of tics and compulsions, it can be hypothesized that a nodal point exists where the shift from “unintentional” to “intentional” repetitive behaviors takes place. Subjective experiences that precede these behaviors may be helpful in defining this demarcation (Miguel et al., 1995), and may be particularly useful to investigate in the subgroup of OCD with tics. OCD patients with tics often report compulsions not preceded by obsessions, and instead usually perform their repetitive behaviors to relieve sensory phenomena (i.e., bodily sensations, general feelings), or to reach a specific sensation or feeling “just-right”


“Studies have reported that patients with tic-related OCD present higher rates of trichotillomania, body dysmorphic disorder (BDD), mood disorderssocial phobia, other anxiety disorders and attention deficit hyperactivity disorder when compared with patients with non-tic-related OCD.”

And here we pause, and consider that the intersection of so many other disorders could be having a synergistic effect on your hair pulling. It would be rare to just have one disorder. It would be rare to just have TTM.

Immune function

“Seminal research has described a subgroup of childhood-onset OCD or tic disorder patients with onset and subsequent exacerbations of their symptoms following infections with group A beta-hemolytic streptococci. This subgroup was designated by the acronym PANDAS: pediatric auto-immune neuropsychiatric disorders associated with streptococcal infections (Swedo et al., 1997). It is hypothesized that PANDAS may arise when antibodies directed against invading bacteria cross-react with basal ganglia structures, resulting in exacerbations of OCD or tic disorders (Swedo et al., 1993; Mell et al., 2005).”

Some hair pullers are now wondering if strep preceded hair pulling or not. Interesting as we have seen more and more research about the gut being the “second brain”. Additionally, some hair pullers found relief from taking NAC which works with the gut in some way. It does take 8 weeks to show results so hang in there if you are trying it. It is interesting to think a virus can “trigger” TS or OCD and possibly TTM as well.

 Deep brain stimulation

Several case reports in TS have described successful results with placement of electrodes in various sites, mainly in the anterior internal capsule, in the medial thalamus and in the globus pallidus internus (Vandewalle et al., 1999Dell'Osso et al., 2005Flaherty et al., 2005Diederich et al., 2005Houeto et al., 2005Ackermans et al., 2006). Different brain areas have been targeted in OCD, with effective results after the stimulation of areas such the anterior limb of the internal capsule (Greenberg et al., 2006).

What is “deep brain stimulation”? Deep brain stimulation involves implanting electrodes within certain areas of your brain. These electrodes produce electrical impulses that regulate abnormal impulses. Or the electrical impulses can affect certain cells and chemicals within the brain. The amount of stimulation in deep brain stimulation is controlled by a pacemaker-like device placed under the skin in your upper chest. A wire that travels under your skin connects this device to the electrodes in your brain.Link to info here.

Anyway, the reviewers not that its not clear is TTM is OCD class of disorder or something else because some studies showed positive effects on a medication that helps with OCD for people with TTM. There has always been discussion on how to class TTM. So no wonder we have poor treatment options.

Repetitive behaviors

“As mentioned earlier, OCD is typically characterized by the presence of both obsessions and compulsions, and often these cover a number of different areas (e.g., checking, washing). In contrast, trichotillomania is typically characterized with a focus solely on hair-pulling. However, there may be some overlap with the phenomenology of OCD; hair-pulling may be triggered by concerns about symmetry, hair-pulling is often performed in a repetitive and ritualistic fashion, and hair-pulling may be preceded by an increase in anxiety and followed by a decrease in anxiety.

On the other hand, functional analysis of hair-pulling, compulsions, and tics often indicates important differences between these symptoms. Tics frequently involve abrupt movements of one or more muscle groups and occur in response to a sensory urge, whereas hair-pulling always involves many muscle groups, resulting in a series of complex movements, with a very specific ‘grooming’ purpose. Similarly, the cognitive mechanisms, such as thought–action fusion, inflated sense of responsibility and the need for control over thoughts, that operate in OCD are not particularly characteristic of either TS or TTM.

One hypothesis has been that hair-pulling occurs in two different forms — focused and automatic. The focused form of hair-pulling is redolent of OCD insofar as it is preceded by anxiety, and results in a decrease in anxiety. However, the automatic form of hair-pulling is rather different; it is somewhat reminiscent of a trance state in that patients are only minimally aware of their behavior at the time that they are doing it, and in that it may be associated with dissociative symptoms. Nevertheless, there has been only some clinical or psychobiological validation of this distinction to date (Woods et al., 2005).”

So it’s interesting they say “We think there are two forms of TTM” meanwhile they presented a figure that had 4 forms that overlapped. So if you are rigid in a “two type of puller” dogma, you miss the complexity and dynamic nature of TTM.


“How similar are TS and TTM to OCD? It seems clear from data on phenomenology, psychobiology, and treatment that TS and TTM are not simply variants of OCD. Nevertheless, some genetic (Pauls et al., 1996) and imaging (Moriarty et al., 1997) data indicate that TS and OCD may have significant overlap in their underlying mechanisms, and TS is arguably the disorder most closely related to OCD. In the case of TTM, there is less information available on underlying psychobiological mechanisms, but there are some data to support an argument that hair-pulling can be conceptualized primarily as a stereotypic disorder, along with conditions such as repetitive skin-picking, which are currently neglected in DSM-IV. Any discussion of the psychobiological validation of a spectrum between TS, TTM, and TTM must, however, be tempered by the admission that our knowledge of the psychobiology of any one of these disorders is currently only partial.

Even in the absence of a full understanding of psychobiology, is there a rationale for conceptualizing OCD, TS, and stereotypic disorders as lying on a spectrum? We would argue that with respect to TTM and stereotypic disorders, the OC spectrum concept has significant conceptual and clinical utility. At a conceptual level, the idea of a spectrum provides a useful framework for integrating data on overlaps as well as differences in the phenomenology, psychobiology, and treatment across these disorders. Thus, for example, work on cortico-striatal-thalamic-cortical circuitry in TS and OCD may shed light on why both disorders are characterized by impulse dyscontrol, but also on why TS is characterized predominantly by motoric symptoms. From a clinical perspective there may be significant utility in emphasizing the different relationships between TS, TTM, and OCD: this reminds clinicians to screen for these otherwise neglected disorders (e.g. stereotypies are typically omitted in screening for common mental disorders), to evaluate important comorbidities (e.g. determining the presence of tics in OCD), and to consider particular treatment options (e.g. although antipsychotics are one of the first line treatments of TS, they may be useful in the augmentation therapy of OCD and TTM). Nevertheless, we are also mindful of the possibility that such an approach may be disadvantageous insofar as TS, TTM, and OCD each require a unique conceptual and clinical framework involving non-overlapping assessment measures and treatment options.”

I didn’t include chunks of the article because some of it was outside the focus of what I was interested in. A review article in itself looks ideas presented by decades of research which vary considerably in how good the data is. For example, they talked at length about how people with TTM compared to a control group to look at “response flexibility” and “spatial thinking” impairments. “Results” showed TTM patients performed worse on every measure practically but only 20 people with TTM were tested. So to me that wasn’t really a good study. I also skipped the animal models because they compared hair pulling to “whisker trimming” behaviors in mice and I just can’t for the life of me find much value in that comparison. Mice models have their value but even in biology, there are limits. You would be surprised how much money a drug company may pump into something that cures something in mice, but fails to do so in humans. So in terms of psychology, I’m not even going to waste my time reading those studies right now. If they were an animal model of “parrot pulling feathers out” studies, then I would be interested in reading that since the comparison is more closely related.

I did find it interesting when they talked about the “spectrum” of OCD, TS and TTM. Considering the picture (figure 1), this suggests the overlaps are representations of a spectrum with specific intersections. This idea is something that could use more work in studying. As a puller, I can identify with the obsessive nature of a pokey hair or wiry hair, but I can also identify with the “trance” state of an automatic puller. So while it may some purpose to categorize some as automatic or focused, we may want to elaborate on the full picture that the binary system misses. If you can track/record a trance, a compulsive pulling episode, a obsessive compulsive “the hair” must be pulled episodes, and a complex assortment of all 3, we might get able to find the internal and external triggers for each type.

Also, realizing you are on a gradient and vulnerable to different types of TTM episodes, could help dictate which treatment you would use and when.

Emily Kight