White matter integrity associated with severity reductions in positive symptoms after amisulpride treatment in drug-free patients with schizophrenia

Amisulpride is an effective antipsychotic for the treatment of schizophrenia with a lower propensity for extrapyramidal adverse effects than conventional antipsychotics. However, no study has investigated white matter (WM) integrity in patients with schizophrenia in relation to treatment response after amisulpride administration. Here, we investigated the associations of WM integrity with severity reductions in clinical symptoms in drug-free patients with schizophrenia at an early stage of amisulpride treatment. Nineteen patients with schizophrenia (SZ) and 15 healthy controls (HCs) participated in the present study. Diffusion tensor imaging data were acquired from all participants at baseline. All SZ participants began treatment with 200 mg of amisulpride per day. The dose was increased up to 1200 mg/day within 2 weeks depending on the severity of clinical symptoms, and maintained for the subsequent 6 weeks. Initially, and after 8 weeks of amisulpride treatment, SZ participants were assessed for the severity of overall illness, positive and negative symptoms, and motor side effects. SZ participants showed lower integrity in several WM regions, including the corpus callosum and fronto-temporal connections, when compared to HCs. Furthermore, lower WM integrity in fronto-temporo-limbic regions at baseline was found to be associated with severity reductions in positive symptoms after 8 weeks. Our findings suggest that WM integrity at the early stage of treatment may serve as a possible predictive marker for treatment response.