Background: Changes in the volume of the caudate nucleus over time in patients with schizophrenia has been shown to be directly related to neuroleptic exposure. Few studies have evaluated caudate volume in subjects with schizophrenia who were neuroleptic naive at intake and treated exclusively with atypical neuroleptics.
Methods: Fourteen patients were matched by gender to 14 healthy controls and were evaluated over time using MRI. The patients were neuroleptic naïve at intake and at follow-up had been treated exclusively with atypical neuroleptics. Difference scores were calculated for caudate volumes. Neuroleptic exposure was quantified using a dose-years formula.
Results: There was no difference between patients and controls in the amount of change over time in the volume of the caudate. However, the female patients had a negative correlation (r= - 0.74) between drug exposure and volume change while the male patients had a positive correlation (r = 0.63). Therefore, there was a significant gender effect on the relationship between atypical neuroleptic exposure and changes in the structure of the caudate over time (test for difference in correlations: z = 2.39, p = 0.016).
Conclusions: The change in caudate nucleus volume over time with exposure to atypical neuroleptics may be sex-dependent. Atypical neuroleptic expsoure was associated with volume increase over time in the males, while exposure in females was associated with volume decrement over time.