New-onset psychosis associated with dandy-walker variant in an adolescent female patient.

The relationship between psychotic disorders, in particular, schizophrenia, and neurodevelopmental abnormalities has been conceptualized in the latest literature. Dandy-Walker variant, defined by cystic dilatation of the fourth ventricle and hypoplasia of the inferior portion of the vermis without enlargement of the posterior fossa, is a distinctive entity believed to represent a mild subtype of Dandy-Walker complex. The authors hypothesize a correlation between new onset of psychosis and cerebellar abnormalities in an adolescent patient.