Comparative Study of Gender Dysphoria Phenomenology and Neurophysiology: Clinical and Experimental Exploration of Gender Identity Disorder

Gender dysphoria is manifested by an internal tension between biological sex and gender, that is, by a non-congruence, in the subjects who suffer from it, between their sex of birth and their social gender identity. Gender dysphoria is accompanied by the often overwhelming need for a hormonal or even hormone-surgical transition. Gender dysphoria is very often characterized by fluctuating mood sadness, irritability, obsessionality. An improvement in the quality of life after medical treatment (hormone therapy) and gender reassignment surgery has been described in the literature. Morphological similarities have been found between the brains of women and the brains of so-called transgender women, as well as between the brains of transgender men and men. These morphological data are only very fragmentary and have not been supported by neuro-functional data. Self-awareness, which refers to the awareness that an individual has of his body, his image and his own identity, is partly underpinned, at the brain level, by the activation of the Default Mode Network (DMN) at rest, in non-pathological conditions. The conflict between the internal perception of the own body and its objective representation could result in a change in brain connectivity within the DMN, due in particular to changes in the activation of the temporo parietal junction.