Few people would claim to like the sound of chewing, lip smacking, or pen clicking. But while disliking these noises is commonplace, experiencing anxiety, panic and/or rage in response to them–a condition called misophonia (hatred of sound)–is not.
Well, truth be told, we don’t actually know how common it is: Searching “misophonia” in PubMed returns just 14 results. Seven were published in 2013/2014, and only three were published prior to 2010. (Searching “selective sensory sensitivity syndrome,” another name for “misophonia” wasn’t particularly fruitful either.)
Interestingly, the most recent paper on misophonia investigated the phenomenon in eating disorder patients. Timely, I thought, given that a few months ago someone had asked me about this very thing on Tumblr. At the time, I came up with nothing. Now I had something. So I posted it on the SEDs Tumblr. The response was almost immediate (click here to read some of the responses). To be honest, I was surprised: I had no idea so many people could relate.
So I thought, it would be important to blog about this paper, which describes ED patients’ experiences with misophonia. In the study, Hannah Kluckow and colleagues screened for misophonia in 15 consecutive patients who had been treated for an eating disorder. Three fulfilled Schröder et al.’s (2013) proposed diagnostic criteria for misophonia.
Kluckow et al. interviewed the patients about their symptoms and symptom history, and assessed their quality of life, misophonia symptoms, and severity of misophonia using questionnaires. I summarized the patients’ information in Table 1 below (click on table to enlarge):
WHAT CAN WE LEARN FROM THESE & OTHER CASES?
For one, it is clear that there is variability in the temporal relationships between ED onset and misophonia onset: one does not necessarily precede the other. In addition, there doesn’t appear to be a relationship between the severity of misophonia and the severity of the ED: severity of misophonia stayed the same or worsened for two patients whose ED symptoms improved.
For two patients, the primary triggers were sounds of chewing, eating, and crunching. I wondered if this might be related to the ED. Are chewing and eating noises common triggers for misophonia patients without an ED? As it turns out, they are.
In a case series of 11 subjects (4 males and 7 females, mean age: 36, age range: 19-65), all participants considered eating, chewing and crunching sounds to be among the worst triggers (Edelstein et al., 2013). Indeed, “eating/chewing/crunching” sounds were the only sounds that were considered a trigger by all participants of the study. (The paper, which is quite interesting, is also freely available online, and has been blogged about by fellow science/research bloggers.)
Several participants (in both studies) reported that they felt particularly bothered when the trigger noises originated from particular individuals. Though most of the participants were not bothered when they themselves were making those noises. Interesting, right?
WHAT ABOUT COMORBIDITIES?
In the Kluckow et al. study, all three patients had features of obsessive-compulsive personality disorder but none fulfilled the diagnostic criteria. In the Edelstein et al. study, only two of the eleven participants had OCPD traits. Conversely, Schröder et al. found that 52% of their sample (22/42 participants) had OCPD.
Schröder et al.:
This high comorbidity does raise the question of whether OCPD is a predisposing factor in the development of misophonia or a consequence of having misophonia. It has been reported previously that some individuals with impulsive aggressive problems develop OCPD symptoms in an attempt to compensate for an underlying problem with behavioural inhibition. This does not hold for our sample because in misophonia the impulsive aggression is only related to certain sounds.
From a phenomenological viewpoint, there appears to be an obsessional part, the focus and preoccupation on a particular sound, and an impulsive part, the urge to perform an aggressive action.
Most patients with OCPD do not have misophonia, but it appears that a substantial portion of patients with anorexia nervosa have OCPD. In a study by Strober et al. (2007), 36% of AN patients met the criteria for OCPD, and OCPD was three times more prevalent among relatives of AN patients than among relatives of healthy controls.
MISOPHONIA, OCPD, and EATING DISORDERS?
In their discussion Kluckow et al. suggest that misophonia, OCD (though I’d say obsessive-compulsive traits), and anorexia nervosa all share the same pathology and/or underlying causes:
It is suggested that misophonia and OCD may share related neurocircuitry with the dysregulation of serotonin and dopamine in the limbic system and basal ganglia. Inefficient dopamine and serotonin utilization can cause exaggerated aversive processing and compulsivity, which are common to misophonia and OCD. The clinical similarities between OCD and misophonia have been discussed in the literature, although they have been delineated as distinct patterns of symptoms.
And as I’ve blogged about before (here, here, here, and here, for starters), serotonin and dopamine systems are affected in AN and BN patients as well. So, maybe there’s a link there? If there is, we are still quite the ways from figuring it all out. After all, searching “eating disorder” in PubMed turns up over 30,000 hits, and we still don’t know all that much about eating disorders. “Misophonia,” as I mentioned earlier, only results in 14 hits.
Obviously, we need more research. It will be important to determine how prevalent misophonia is among ED patients. Is it more prevalent among ED patients than healthy controls? What about those with anxiety disorders? And if it is more prevalent among ED patients, why is that and what does it mean? How are they related? It will also be important to study whether misophonia is (or could be) involved in causing, maintaining, or exacerbating ED symptoms, and of course, how we can treat it, particularly in the context of eating disorders.
Finally, in Kluckow et al.’s study, only one out of the three patients reported misophonia symptoms to a therapist, which suggests that it might be wise for clinicians and therapists treating ED patients to screen for misophonia. Not only to further research on this topic but also to facilitate communication and enable patients to talk freely about their symptoms and how they may (or may not) affect their eating disorder.
Edelstein M, Brang D, Rouw R, & Ramachandran VS (2013). Misophonia: physiological investigations and case descriptions. Frontiers in Human Neuroscience, 7 PMID: 23805089
Kluckow H, Telfer J, & Abraham S (2014). Should we screen for misophonia in patients with eating disorders? A report of three cases. International Journal of Eating Disorders PMID: 24431300
Schröder A, Vulink N, & Denys D (2013). Misophonia: diagnostic criteria for a new psychiatric disorder. PloS one, 8 (1) PMID: 23372758