Measurement of the serotonin 1A receptor availability in patients with schizophrenia during treatment with the antipsychotic medication ziprasidone

The aim of this study was to compare 5-HT1A availability in'vivo in individuals with schizophrenia before and during treatment with the atypical antipsychotic ziprasidone. Six individuals with schizophrenia underwent two PET scans with [11C]WAY 100635; the first while medication-free (baseline) and the second while taking the atypical antipsychotic ziprasidone (on-medication). Regional volumes of distribution (VT, mL g?1) were derived using a two-tissue compartment kinetic model. Outcome measures included binding potential relative to the plasma (BPP, mL g?1) and the binding potential relative to the nonspecific distribution volume (BPND, unitless). No significant differences were observed in regional BPP or BPND with ziprasidone treatment. A significant correlation was noted between BPP measured in the orbitofrontal cortex during the on-medication condition and degree of improvement in negative symptoms with treatment (r = 0.96, p = 0.004). Consistent with the published literature of changes in 5-HT1A binding during treatment with 5-HT1A receptor agonists, this study did not detect a significant reduction in 5-HT1A binding with ziprasidone. The finding of a relationship between 5-HT1A binding and the degree of improvement in negative symptoms provides further support for the role of the 5-HT1A receptor in the pathophysiology and treatment of this symptom domain.