Chlorpromazine versus placebo for schizophrenia
Bibliographic record
Abstract
BACKGROUND: Chlorpromazine, formulated in the 1950s, remains a benchmark treatment for those with schizophrenia. OBJECTIVES: To evaluate the effects of chlorpromazine for schizophrenia in comparison to placebo. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), The Cochrane Library (1999, Issue 2), The Cochrane Schizophrenia Group's Register (October 1999), EMBASE (1980-1995), MEDLINE (1966-1995), PsycLIT (1974-1995) were undertaken. References of all identified studies were searched for further trial citations. Pharmaceutical companies and authors of trials were contacted. SELECTION CRITERIA: Randomised controlled trials relating to people with schizophrenia, and non-affective serious/chronic mental illness irrespective of mode of diagnosis evaluating chlorpromazine (any dose) versus placebo. Primary outcomes of interest were death, violent behaviours, overall improvement, relapse and satisfaction with care. DATA COLLECTION AND ANALYSIS: Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were extracted by BT with CA and GA independently checking a 10% sample for reliability. Dichotomous data were analysed using random effects relative risk (RR) and the 95% confidence interval around this was estimated. Where possible the number needed to treat (NNT) or number needed to harm statistics (NNH) were calculated. Continuous data were excluded if more than 50% of people were lost to follow up, but, where possible, weighted mean difference was calculated. Sensitivity analyses have not been undertaken for this version of the review. MAIN RESULTS: Over 1000 electronic records were inspected. The review currently mentions 202 papers in its Excluded Studies section and 45 studies in its Included Studies table. Six papers await assessment. Chlorpromazine reduces relapse over six months to two years (RR 0.65 CI 0.5-0.9, NNT 3 CI 2.5-4) and there is convincing evidence from trials that it promotes a global improvement in a person's symptoms and functioning (RR 0.76 CI 0.7-0.9, NNT 7 CI 5-10) although the placebo response is also considerable (nearly 40%). Fewer people allocated to chlorpromazine leave trials early (RR 0.76 CI 0.6-1.1). There are many adverse effects. Chlorpromazine is clearly sedating (RR 2.4 CI 1.7-3.3, NNH 6 CI 4-8), it increases a person's chances of experiencing acute movement disorders (RR 3.1 CI 1.3-7.6, NNH 24 CI 14-77), parkinsonism (RR 2.6 CI 1.2-5.4, NNH 10 CI 8-16) and fits (RR 2.4 CI 0.4-16). Amongst other things it clearly causes a lowering of blood pressure with accompanying dizziness (RR 1.9 CI 1. 3-2.6, NNH 12 CI 8-22) and considerable increases in weight (RR 4.4 CI 2.1-9, NNH 3 CI 2-5). REVIEWER'S CONCLUSIONS: This review will confirm much that clinicians and recipients of care already know but provides quantification to support clinical impression. Despite the humbling 40% improvement rate in those who were allocated to placebo, chlorpromazine's global position as the 'benchmark' treatment of those with psychoses is not threatened by this review. Chlorpromazine, in common use for nearly half a century, is a well established but imperfect treatment. Judicious use of this best available evidence should lead to better informed decisions both by carers and those with psychotic illnesses.
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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 | 0.009 | 0.016 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.004 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.018 | 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".