Corpus Callosum Agenesis and Psychosis in Andermann Syndrome

• Recent illustrations by cerebral magnetic resonance imaging of anomalies of the corpus callosum in schizophrenics have kindled renewed interest in this association. We studied 62 patients affected by the Andermann syndrome, a polymalformative familial syndrome combining frequent congenital corpus callosum agenesis, mental retardation, psychotic episodes, peripheral neuropathy, and some dysmorphic features. Twenty of 62 patients presenting with psychosis were compared with 20 nonpsychotic patients matched according to sex and age. The psychotic patients presented an atypical psychosis as defined by the Diagnostic and Statistical Manual of Mental Disorders, Third Edition , beginning in postadolescence. No significant relationship was observed between corpus callosum agenesis and psychosis. However, a significant association between posterior fossa atrophy and psychosis was established in our study. Although there are limitations in using cross-sectional data for this purpose, the findings suggest an association between cerebellar anomalies and schizophrenialike syndrome and rule out an implication of developmental callosal defects in such psychiatric disorders.