The co-occurrence of Schizophrenic psychoses (with sex changes delusional experiences or themes) and gender dysphoria has been debated since the end of 19 th century with different accents: as an association of sexual psychopathy and paranoia, for the possible etiopathogenetic role of bi-sexuality and gender dysphoria in different psychic disorders, as psychopathologies that needed to be accurately differentiated, and, at last, as co-occurring conditions that can interfere each to the other.
The Authors describe in detail the clinical case of a 54 years old man who in relation with the periodic sharpening of his schizo-affective maniform psychosis, showed temporary shameless, grotesque and even bizarre cross-dressing behavior and sex re-assignment request. In euthymic or depressive phase, his transexual behavior was much less evident or even repressed. The psychopathological implications of this rare but impressive co-occurrence are discussed.