Sex Change Hormones May Alter Brain Chemistry, Depression Risk

Hormonal treatments given as part of the sex reassignment process alters an individual’s brain chemistry, increasing the risk of depression in male-to-female transexuals and lowering the risk in female-to-males, according to a new study published in the journal Biological Psychiatry. The process aligns the transexual’s risk of depression with the established risk of their desired gender.

Researchers and doctors have long known and documented the bodily effects of gender reassignment hormonal treatments. These hormones greatly alter the secondary sexual characteristics of the adult body, shifting a recipient’s physical appearance to that of the opposite sex. Changes occur involving hair growth and texture, voice, muscle tone, complexion, and overall body shape.

Less is known, however, about the brain chemistry changes involved in sex reassignment. In order to investigate this issue further, researchers at the Medical University of Vienna conducted a study evaluating the depression risk in individuals going through gender reassignment procedures.

They found that the administration of the male hormone testosterone in female-to-male transsexuals raises brain levels of SERT, the protein that transports the chemical messenger serotonin into nerve cells. In contrast, male-to-female transsexuals who received a testosterone blocker and the female hormone estrogen showed decreased levels of SERT in the brain.

SERT plays an important role in the treatment of mood and anxiety disorders. Many common antidepressants, such as Prozac, block its activity by inhibiting serotonin reuptake. In addition, some genetics studies have suggested that higher levels of SERT may increase resilience to stress and reduce risk for stress and mood disorders.

Because women are twice as likely to be diagnosed with depression as men, these changes in the levels of SERT are consistent with the increased risk for mood and anxiety disorders in females compared to males.

“These results may explain why testosterone improves symptoms in some forms of depression. Our study also increases our knowledge on the role of sex hormones in sex differences of mood disorders,” said senior co-author Dr. Rupert Lanzenberger. He conducted the study with Dr. Siegfried Kasper.

Overall, these findings suggest that when people switch from female to male, their biology changes in a way that is consistent with a reduced risk for mood and anxiety disorders, whereas the reverse happens when males switch to females.

“This study is the first to show changes in brain chemistry associated with the hormonal treatments administered in the sex change process,” said Dr. John Krystal, editor of the journal Biological Psychiatry, where the study was published. “It provides new insight into the ways that the hormonal differences between men and women influence mood and the risk for mood disorders.”

Source: Elsevier