Background. Familial idiopathic basal ganglia calcification (FIBGC) is generally associated with neurological and psychiatric symptoms. An association between FIBGC and schizophrenia has been described but it remains uncertain. We studied the relationship between the presence and extent of basal ganglia calcification and schizophrenia in a multiply affected family.

Method. Symmetrical basal ganglia calcifications (BGC) were detected on computerized tomography (CT) in a schizophrenic proband and led us to carry out CTs and standardized psychiatric evaluations (SADS – Endicott & Spitzer, 1978) in all available first-degree relatives (mother and six siblings).

Results. Five subjects had BGC, including three subjects diagnosed as schizophrenic. Three subjects had no BGC and none of them was diagnosed as schizophrenic. We subdivided the BGC into three groups: massive (pallidum, striatum and dentate nuclei affected); medium (pallidum and striatum); and mild (pallidum only). The two subjects with massive BGC and one of the two with medium BGC had schizophrenia. The subject with mild BGC had no psychotic symptoms.

Conclusion. Our results are consistent with the hypothesis that BGC favours the occurrence of a schizophrenia-like syndrome and that the risk of occurrence of this syndrome is proportional to the extent of calcification. These findings support the hypothesis that schizophrenia is determined by a disruption of thalamo–cortico–striatal circuits.