Study of "gender dysphoria" in the brain has long missed one possible cause

After reviewing decades of previous research, a new study suggests that scientists have overlooked a potential cause for the condition known as gender dysphoria, or when a person lives with a mismatch between their assigned gender and their true sense of gender identity. The finding could open the door for more helpful therapy for people who are struggling to live with the condition.

Stephen Gliske, a researcher at the University of Michigan, suggests scientists have been too focused on physical differences in the brains of men and women.

Many scientists thought that gender dysphoria arose from incorrect “brain sex” — in other words, anatomical differences in the brain. The theory goes that the brains of people with gender dysphoria look more similar to those of the opposite sex than the one they were assigned at birth.

As a result, researchers have long have overlooked dynamic ways different parts of the brain function and interact, or network, with each other. It might be that brain networks are the cause for gender dysphoria, Gliske’s paper argues.

“Many of the brain differences associated with gender dysphoria are located in the distress, body-ownership and social behavior networks,” Gliske tells Inverse.

Gliske’s research, compiled in this peer-reviewed article, was published Monday in the journal eNeuro.

Gender dysphoria can be extremely stressful: People with the condition often experience chronic distress, gender nonconformity, and incongruence between perception of gender identity and body sex. The condition can occur at any age.

Experts estimate that of the 700,000 people who are transgender in the United States, many will feel the affects of gender dysphoria on their mental health, in addition to the discrimination and violence they might experience. Despite its prevalence, scientists are still learning about how and why gender dysphoria occurs.

This new study shifts the focus away from brain differences to how people sense and perceive their gender, as shaped by these neural networks, Gliske says.

“Rather than focusing on whether the brain regions are masculine or feminine, this new theory explains how the function of these networks impacts one’s sense of their own gender.”

Neural networking

The study drills down on three specific neural networks associated with distress, social behavior, and body-ownership.

• The distress network appears to be tied to the amygdala, which regulates mood, fear, anxiety, and stress — all of which are associated with gender dysphoria.
• The social behavior network seems to dictate how people behave sexually, as parents, and how aggressive they are.
• Lastly, the body-ownership network may control how an individual relates to their body — how they sense and perceive their arms, toes, or sexual anatomy, for example.

Gliske argues that changes in these networks drive gender dysphoria, and could lead to the changes in brain size and shape that have been previously linked to the condition.

Ultimately, rethinking gender dysphoria’s underpinnings in the brain could lead to new, less invasive treatments for the condition beyond gender reassignment surgery or procedures that endanger a person’s fertility long-term, he says.

Before we get there, more research is needed on this largely understudied and misunderstood population. Scientists don’t know how these networks interact or how they may lead to gender dysphoria, for example.

But Gliske’s theory does open the door to alternative therapies that target distress and people’s sense of body ownership. These therapies could be less expensive and invasive, and improve the quality of life of thousands of people around the world who have gender dysphoria now, he says — that way, researchers can catch up.

Abstract:

When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over two decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans. We hypothesize that in individuals with gender dysphoria, the aspects of chronic distress, gender atypical behavior, and incongruence between perception of gender identity and external primary sex characteristics are all directly related to functional differences in associated brain networks. We evaluated previously published neuroscience data related to these aspects and the associated functional networks, along with other relevant information. We find that the brain networks that give individuals their ownership of body parts, that influence gender typical behavior, and that are involved in chronic distress are different in individuals with and without gender dysphoria, leading to a new theory—that gender dysphoria is a sensory perception condition, an alteration in sense of gender influenced by the reflexive behavioral responses associated with each of these networks. This theory builds upon previous work that supports the relevance of the body ownership network and that questions the relevance of cerebral sexual dimorphism in regards to gender dysphoria. However, our theory uses a hierarchical executive function model to incorporate multiple reflexive factors (body ownership, gender (a)typical behavior, and chronic distress) with the cognitive, reflective process of gender identity.