A Cross-Sectional Study of Plasma Risperidone Levels With Risperidone Long-Acting Injectable
Bibliographic record
Abstract
Article Abstract Objective: While 65%-80% occupancy of dopamine D2 receptors with antipsychotics has been proposed to achieve optimal therapeutic response during acute treatment of schizophrenia, it remains unclear as to whether it is also necessary to maintain D2 receptor occupancy within this "safe" window for ongoing maintenance treatment. The data are especially scarce for long-acting antipsychotic formulations. Method: Clinically stable patients with schizophrenia (DSM-IV) receiving a stable dose of risperidone long-acting injectable (LAI) as antipsychotic monotherapy for at least 3 months and free of any psychiatric hospitalization over the past 6 months were included. Dopamine D2 receptor occupancy levels at trough were estimated from plasma concentrations of risperidone plus 9-hydroxyrisperidone immediately before the intramuscular injection of risperidone LAI, using a 1-site binding model derived from our previous positron emission tomography data. This study was conducted from October to December 2011. Results: 36 patients were included in this study (mean±SD age, 49.3±14.0 years; mean±SD dose and interval of injections, 38.2±11.6 mg and 16.5±14.0 days, respectively). Mean±SD D2 receptor occupancy was 62.1%±15.4%; 52.8% of the subjects (n=19) did not demonstrate an occupancy of ≥65%. On the other hand, 13.9% (n=5) showed a D2 occupancy as high as over 80% at the estimated trough. Conclusions: More than half of patients taking risperidone LAI maintained clinical stability without achieving continuous blockade of dopamine D2 receptors ≥65% in real-world clinical settings. Results suggest that sustained dopamine D2 receptor occupancy levels of ≥65% may not be necessary for maintenance treatment with risperidone LAI in schizophrenia. J Clin Psychiatry 2012;73(8):1147-1152 © Copyright 2012 Physicians Postgraduate Press, Inc. Submitted: January 6, 2012; accepted April 9, 2012 (doi:10.4088/JCP.12m07638). Corresponding author: Hiroyuki Uchida, MD, PhD, Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan (mcn41320@biglobe.ne.jp).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".