Long-term stability of measuring D2 receptors in schizophrenia patients treated with antipsychotics

BackgroundWhile antipsychotic-free schizophrenia patients showed a high degree of within-subject variability in dopamine D2 receptor density over 6–24 months, no study has examined the long-term stability of D2 receptor measures in medicated patients.MethodsFour schizophrenia patients receiving a stable dose of risperidone underwent [11C]raclopride positron emission tomography scans on two occasions 5–14 months apart.ResultsPlasma risperidone levels were found to be consistent between scans, and consistencies of nondisplaceable D2 binding potential and D2 occupancy were good.ConclusionsThe finding supports the validity of quantification of D2 receptor binding in longitudinal PET studies of medicated patients with schizophrenia.