The Neuroscience of Body-Focused Repetitive Behaviors
Neuroscience continues to investigate the difference between a bad habit and the spectrum of mental health disorders known as body-focused repetitive behaviors (BFRBs). BFRBs afflict less than 3% of the population, mostly women. Symptoms usually start in conjunction with the onset of puberty and last a lifetime.
Diagnoses within the BFRB category include trichotillomania or compulsive hair pulling, excoriation disorder or compulsive skin picking, and nail–biting. While some people may have a habit of pulling out hair, picking at skin, or biting nails, people with these disorders engage in these behaviors to the point of physical damage. Those with trichotillomania will have bald spots, damaged hair follicles, odd hair growth patterns. People who struggle with skin picking end up with scabs, scars, skin infections, and other evidence of skin damage. Additionally, they may spend hours at a time pulling, picking, or biting to the point where they have to spend time covering up the damage. Despite the physical damage and multiple attempts to quit the behavior, the compulsions and urges to pull, pick or bite continue.
“Research on BFRBs is challenging because of the subtle differences between the multiple subtypes.”
There are subtypes of BFRBs based on how someone engages in the behaviors. For some people, it is a focused behavior where the act of pulling, picking, or biting serves a purpose, such as emotional release. For others, it is an automatic process where the behaviors occur outside the person’s awareness, such as when one is bored or zoned out, only to come to the present and notice the physical evidence of what they’ve done.
The compulsions of BFRBs hint at a connection to obsessive-compulsive disorder (OCD). Yet while they exist within the OCD spectrum of mental health disorders (according to psychiatry’s diagnostic categories), BFRBs are different from OCD. Research on BFRBs is challenging because of the subtle differences between the multiple subtypes of behaviors such as focused and automatic or hair pulling and skin picking. Moreover, the low prevalence rates and the stigma attached to these disorders makes recruiting participants with the same type of BFRB for research difficult. Despite the limitations of research, here is what we know.
BFRBs are different from OCD
Brain imaging studies of people with OCD and trichotillomania suggest that each condition is represented neurologically. Chamberlain and colleagues (2017) looked at MRI scans of people with trichotillomania compared to a healthy control group to determine if there were structural differences in the area of the brain involved in mediating habit suppression. In the trichotillomania group, researchers found significantly increased thickness in a part of the brain called the inferior frontal gyrus. This part of the brain is involved in the suppression of inappropriate motor responses. For example, a person who fidgets will often engage that part of the brain when making the conscious effort to stop fidgeting. In people with trichotillomania, that mechanism that allows you to take control of the inappropriate motor response does not function the same way. In contrast, brain scan studies of people with OCD show reduced thickness in that part of the brain. Therefore, the increased thickness in trichotillomania versus the decreased thickness in OCD suggests that the neurological basis for trichotillomania is different from OCD.
“People with compulsions have a higher degree of connectivity between the orbitofrontal cortex and the basal ganglia.”
Areas of the brain
In addition to the areas of the brain responsible for stopping inappropriate motor responses, there are other areas of the brain associated with impulsivity and compulsivity. The drive for impulsivity is reward, which can explain part of the focused behaviors of people with BFRBs who report feeling pleasure, gratification, or emotional release from the behaviors. In the case of dysfunctional impulsivity, there is evidence for a malfunction of the dopamine reward system in the brain (Flessner, Knopik & McGeary, 2012) as well as alteration in the functioning of the anterior cingulate (Pompanin et al., 2014). On the other hand, compulsivity is a need to avoid harm. People with compulsions have a higher degree of connectivity between the orbitofrontal cortex and the basal ganglia according to research using participants with obsessive-compulsive disorder (Beucke, Sepulcre, & Talukdar, 2013). With this hyper connectivity, the circuit of learning and rewards is hyperactivated and the hypothesis is that the compulsive behavior becomes a learned activity due to the malfunctioning hyper connection. More research is needed, though, before conclusions can be generalized to BFRBs.
“People who do not struggle with BFRBs may ask, ‘Isn’t it painful?'”
Research into different brain areas related to BFRBs is supported by imaging of dementia patients who develop BFRBs after never having them before in their lives. In one case study, a 64-year old woman with dementia began experiencing changing food cravings, then overeating, eventually followed by the addition of obsessive thoughts, compulsive eating and smoking and finally, compulsive skin picking (Pompanin et al., 2014). The progression of this woman’s symptoms along with the addition of multiple compulsive behaviors provided researchers evidence that the decreasing functioning of neuronal circuits and changes in the brain areas noted previously provide the beginnings of a neurological basis for BFRBs.
Pain receptor malfunction
People who do not struggle with BFRBs may ask, “Isn’t it painful?” This question is especially relevant for people with compulsive skin picking disorder, because many of them pick their skin until wounds form. Pain is a result of wounding the skin, but it also results in pain following the episodes, while healing and sometimes because of infection.
“Which comes first, the stress or the behaviors?”
A recent study (Grant, Redden & Chamberlain, 2017) evaluated the pain receptors of people with excoriation disorder to determine if they feel less pain. Researchers used the cold pressor pain test with a group of people with skin picking disorder and a control group without the disorder. The cold pressor pain test involves participants putting their hand in ice cold water until it becomes unbearable. In research, the cold pressor pain test shows activation of the amygdala and anterior cingulate cortex, which are the same parts of the brain that light up in response to negative emotional experiences, like getting hurt. Researchers believed that people with skin picking disorder would report less discomfort and increased pain tolerance in the cold pressor test. The results supported the hypothesis, so participants with skin picking disorder did experience a dampened autonomic response to pain, but they experienced pain the same as the control group. The finding is significant in that it shows that although a person’s response to pain is lower in the case of excoriation disorder, they still experience it; therefore, the body and brain’s reaction to pain may be slow, but pain is still felt. Picking behaviors might thus desensitize someone to pain. If someone doesn’t feel the alarm and stress associated with picking at their skin, perhaps treatment interventions that trigger the stress response may help people stop the harmful picking behaviors.
Stress and BFRBs
Increased stress positively correlates with increased severity of the BFRB. People with high stress experience more severe compulsive behaviors. However, those studies also show that those people with more severe behaviors experience increased stress. The question not answered is: which comes first, the stress or the behaviors?
The ability of someone to build a tolerance to the pain associated with BFRBs and the relationship between stress and severity of behaviors shows that the compulsion or the inability to stop the behavior is a driving force. While neuroscience has a long way to go before providing the brain-based evidence of why BFRBs occur, we know that a different part of the brain directs those behaviors and it is likely the part that is responsible for stopping habitual behaviors.
Beucke, J. C., Sepulcre, J. & Talukdar, T. (2013). Abnormally high degree connectivity of the orbitofrontal cortex in obsessive-compulsive disorder. JAMA Psychiatry, 70(6), 619-629. Doi: 10.1001/jamapsychiatry.2013.173
Chamberlain, S. R., Harries, M., Redden, S. A., Keuthen, N. J., Stein, D. J., Lochner, C. & Grant, J. E. (2017). Cortical thickness abnormalities in trichotillomania: International multi-site analysis. Brain Imaging and Behavior. https://doi.org/10.1007/s11682-017-9746-3
Flessner, C. A., Knopk, V. S., & McGeary, J. (2012). Hair pulling disorder (trichotillomania): Genes, neurobiology, and a model for understanding impulsivity and compulsivity. Psychiatry Research, 199, 151-158. Doi: 10.1016/j.psychres.2012.03.039
Grant, J. E. & Chamberlain, S. R. (2017). Clinical correlates of symptom severity in skin picking disorder. Comprehensive Psychiatry, 78, 25-30. https://www.ncbi.nlm.nih.gov/pubmed/28779593
Grant, J. E., Redden, S. A., & Chamberlain, S. R. (2017). Cold pressor pain in skin picking disorder. Psychiatry Research, 249, 35–38. http://doi.org/10.1016/j.psychres.2016.12.050 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5345741/
Pompanin, S., Jelcic, N. Cecchin, D. & Cagnin, A. (2014). Impulse control disorders in front o temporal dementia: Spectrum of symptoms and response to treatment. General Hospital Psychiatry, 36, 760.e5-760.e7. Doi: 10.1016/j.genhosppsych.2014.06.005
By: Trudi Griffin – a Licensed Professional Counselor putting her clinical knowledge, experience, and passion for research to write about mental health. Trudi is part of the Trichstop.com team.