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Relationship Between Dopamine D<sub>2</sub> Occupancy, Clinical Response, and Side Effects: A Double-Blind PET Study of First-Episode Schizophrenia

2000· article· en· 1,083 citations· W2099185967 on OpenAlex· 10.1176/appi.ajp.157.4.514

Why is this work in the frame?

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

Canadian affiliationAn author listed a Canadian institution. This is the only route the usual frame has.

Full frame distilled prediction

Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

Candidate categories
none
Consensus categories
none
Domain
Candidate signal: noneConsensus signal: none
Study design
Candidate signal: ObservationalConsensus signal: Observational
Genre
Candidate signal: EmpiricalConsensus signal: Empirical
Teacher disagreement score
0.181
Threshold uncertainty score
0.942
Validation status
machine_predicted_unvalidated · codex-gemma-dda1882f352a

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0020.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

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.

Opus teacher head0.037
GPT teacher head0.360
Teacher spread
0.322 · how far apart the two teachers sit on this one work
Validation status
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Abstract

OBJECTIVE: Since all antipsychotics block dopamine D(2) receptors, the authors investigated how well D(2) receptor occupancy in vivo predicts clinical response, extrapyramidal side effects, and hyperprolactinemia. METHOD: In a double-blind study, 22 patients with first-episode schizophrenia were randomly assigned to 1.0 or 2. 5 mg/day of haloperidol. After 2 weeks of treatment, D(2) receptor occupancy was determined with [(11)C]raclopride and positron emission tomography, and clinical response, extrapyramidal side effects, and prolactin levels were measured. Patients who showed adequate responses continued taking their initial doses, those who did not respond had their doses increased to 5.0 mg/day, and evaluations were repeated at 4 weeks for all patients. RESULTS: The patients showed a wide range of D(2) occupancy (38%-87%). The degree of receptor occupancy predicted clinical improvement, hyperprolactinemia, and extrapyramidal side effects. The likelihood of clinical response, hyperprolactinemia, and extrapyramidal side effects increased significantly as D(2) occupancy exceeded 65%, 72%, and 78%, respectively. CONCLUSIONS: The study confirms that D(2) occupancy is an important mediator of response and side effects in antipsychotic treatment. The data are consistent with a "target and trigger" hypothesis of antipsychotic action, i.e., that the D(2) receptor specificity of antipsychotics permits them to target discrete neurons and that their antagonist properties trigger within those neurons intracellular changes that ultimately beget antipsychotic response. While limited to haloperidol, the relationship between D(2) occupancy and side effects in this study helps explain many of the observed clinical differences between typical and atypical antipsychotics.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

The record

Venue
American Journal of Psychiatry
Topic
Schizophrenia research and treatment
Field
Medicine
Canadian institutions
University of Toronto
Funders
not available
Keywords
AntipsychoticDopamine receptor D2Extrapyramidal symptomsHaloperidolRacloprideInternal medicineSchizophrenia (object-oriented programming)MedicinePsychologyPsychosisDopamineEndocrinologyPharmacologyOncologyPsychiatry
Has abstract in OpenAlex
yes