Do you know the underlying neurobiological bases of body dysmorphic disorder? If you want to know them and learn more, keep reading!

Body Dysmorphic Disorder (BDD) is characterized by excessive preoccupation with one or more physical characteristics; the person identifies a physical defect in them and overestimates its importance on a social level (APA, 2014).

Those with this disorder spend a lot of time focused on their imperfections and how to hide them. Your negative thoughts can consume most of your days, interfering with quality of life and your ability to carry out daily activities.

The prevalence of BDD ranges from 0.7% to 2.5%, reaching 12% in obsessive-compulsive patients . Regarding gender, the prevalences are very similar, although there are slight differences in the part of the body that causes concern. In men, the perception of the most common defect focuses on the genitals, body structure, and hair, while in women concerns tend to fall on the skin, abdomen, and weight (Rincon, 2022).

In this article we will address the neurobiological support of this disorder and we will review what some research tells us about its etiology at a cortical level. Let’s go deeper.

People with BDD show excessive concern about their own body image.

The left hemisphere of the brain in people with BDD

One investigation did not identify significant alterations in the brains of people with BDD; what was seen is that they work abnormally when processing visual details . This finding was one of the first to support the idea that there is a neurobiological correlate for distorted body image in patients with this disorder.

“Our discovery suggests that the hardware of the TDC brain is fine, but there is a flaw in the operating software that prevents patients from seeing themselves as others do,” explained lead researcher Dr. Jamie Feusner.

To develop this research, functional magnetic resonance imaging (fMRI) was used with the aim of observing how the brains of the participants processed visual information. To do this, the researchers fitted 12 BDD patients with special glasses that allowed them to view digital photos of various faces while undergoing a brain scan.

Each participant observed three types of images. The first type was an intact photo. The second type was a photo altered to remove facial details, such as freckles, wrinkles, and scars. The third type of image had significantly altered faces.

an amazing find

The researchers compared the responses of BDD patients with 12 control subjects. What they observed surprised them all.

“We saw a clear difference in how the right and left brains functioned in people with BDD compared to those without the disorder,” Feusner said.

The BDD patients used more often the left side of their brain, the analytical side attuned to complex details, even when processing the less complex, low-frequency images. Their left hemispheres were activated regardless of the type of image. In contrast, in healthy people, the left side was only activated to interpret the information from the images that had been most altered.

“The findings suggest that BDD brains are hardwired to extract details, or fill in details where they don’t exist. They may be thinking of their own face even when looking at others,” Feusner said.

This study also found that limitations in number and severity were positively associated with the intensity with which the left hemisphere was activated during visual processing.

Neurocognitive functioning in body dysmorphic disorder

In 1998, Hanes found that people with BDD and OCD performed poorly relative to healthy controls on tests of executive function, including response inhibition and planning. On the other hand, a 2010 study found that participants with BDD made significantly more errors on spatial working memory tasks and had slower thinking times on a Stockings of Cambridge test , used to investigate deficits in memory. planning.

Other neuropsychological studies in people with body dysmorphic disorder have highlighted that these patients seem to have deficits in facial recognition of emotions . In fact, it has been found that, in self-referential situations, BDD patients are more likely to misinterpret neutral faces as angry or contemptuous.

Neurochemistry of BDD Brains

A reduction in the serotonin transporter has been found in OCD-related disorders, including BDD. In addition, results from various studies indicate that selective serotonin reuptake inhibitor (SSRI) medications are effective for the treatment of BDD (Ipser, 2010; Phillips & Hollander, 2008).

Furthermore, treatment with SSRIs reduces the frequency and intensity of the worries . Furthermore, it improves control over impulsivity and decreases the distress associated with BDD (Allen et al., 2008; Phillips & Hollander, 2008).

Other studies  on the participation of serotonin in BDD indicate that the symptoms of this disorder intensify as tryptophan (serotonin precursor) in the diet is reduced . They also show that the serotonin agonist psilocybin attenuates the symptoms of body dysmorphic disorder.

The symptoms of BDD intensify when tryptophan decreases.

Neuroanatomy of body dysmorphic disorder

Research conducted by Grace in 2017 and 2019 showed that patients with BDD had hypoactivity in the lateral occipital cortex (related to visual processes) and the precuneus (related to face recognition), particularly within the left hemisphere. This affects the visual processing of information associated with faces and figures. Other results reveal a possible alteration in the fronto-striate and temporo-parieto-occipital circuits (where facial images and emotional information are processed ).

Taking the above into account, Li et al. (2013) state that visual perceptual disturbances, along with frontostriatal and limbic system dysfunction, may combine to contribute to BDD symptoms such as perceptual impairment, obsessive thoughts, and compulsions .

Finally, body dysmorphic disorder is a complex psychiatric disorder in which various environmental and biological factors converge. Its neurobiological foundation is still not clear and definitive, however, the results of the research that we have reviewed give us insight to understand a little more how the brain of patients who suffer from it works.