Twenty-eight psychiatric patients with computerized tomography (CT) findings of ventricular abnormality most likely to result from prenatal/perinatal lesions (VA group) were compared to 28 sex- and age-matched psychiatric patients with normal neuroradiological findings (NCT group). The neuroradiological rater was blind to clinical psychiatric diagnoses and, vice versa, clinical diagnoses were established without knowledge of neuroradiological findings. A polydiagnostic approach (DSM-III-R, ICD-10, Leonhard Classification) was used for psychiatric diagnostic workup. Significantly more patients with cycloid psychoses (according to Leonhard's original description) were found in VA as compared to NCT patients. According to DSM-III-R and ICD-10, VA and NCT groups did not differ significantly regarding diagnostic distribution. Ventricular abnormalities that may reflect sequels of birth complications and/or adverse events during pregnancy may constitute one of the risk factors for developing cycloid psychosis as originally described by Leonhard.