Dorsal striatal volumes in never-treated patients with first-episode schizophrenia before and during acute treatment

Studies of pre-and post-treatment striatal volume in schizophrenia have reported conflicting results.

We assessed dorsal striatal (caudate and putamen) volumes bilaterally in 22 never-treated, non-substance-abusing patients with first-episode schizophrenia or schizophreniform disorder and 23 healthy controls matched for age, sex and educational status. Patients received either risperidone or flupenthixol long acting injection and were compared by structural MRI with controls at weeks 0, 4 and 13. T1-weighted data on a 3T MRI scanner were obtained and images were reconstructed using FreeSurfer. Treatment outcome was assessed by changes in psychopathology, insight, functionality, cognitive performance and motor symptoms.

Caudate, but not putamen volumes was significantly larger in patients bilaterally at baseline (P=0.01). Linear mixed effects repeated measures found no significant group × time interactions for any of the regions. Caudate volume was not significantly associated with improvements in psychotic symptoms. Also, the findings of a regression model were inconsistent insofar as larger caudate volume was associated with less improvement in depression scores, greater improvement in functionality and greater improvement in verbal learning but less improvement in reasoning and problem solving (left caudate) and composite cognitive score (right caudate).

The increased caudate volumes prior to treatment are contrary to previous reports in never-treated patients with first-episode schizophrenia, and together with our failure to demonstrate volume changes related to acute treatment, call into question previous proposals that enlarged caudate volume is a consequence of antipsychotic treatment.