Serum concentrations of brain-derived neurotrophic factor in patients with gender identity disorder.

Gender Identity Disorder (GID) is characterized by a strong and persistent cross-gender identification that affects different aspects of behavior. Brain-derived neurotrophic factor (BDNF) plays a critical role in neurodevelopment and neuroplasticity. Altered BDNF-signaling is thought to contribute to the pathogenesis of psychiatric disordersand is related to traumatic life events. To examine serum BDNF levels, we compared one group of DSM-IV GID patients (n = 45) and one healthy control group (n = 66). Serum BDNF levels were significantly decreased in GID patients (p = 0.013). This data support the hypothesis that the reduction found in serum BDNF levels in GID patients may be related to the psychological abuse that transsexuals are exposed during their life.