Heroin and cocaine co-use in a group of injection drug users in Montréal
Bibliographic record
Abstract
OBJECTIVE: To describe the pattern of co-use of heroin and cocaine in individuals who were not receiving methadone maintenance treatment. DESIGN: Structured interviews. SETTING: Community hospital. PARTICIPANTS: Individuals (n = 1111) selected from a cohort of out-of-treatment injection drug users in Montréal, Que. OUTCOME MEASURE: Frequency (injections per day) and quantity (number of days of use) of heroin, cocaine and speedball (the simultaneous administration of heroin and cocaine) use reported in the month preceding the interview. RESULTS: About 50% of the sample reported using only cocaine intravenously (C group), about 8% reported using only heroin (H group) intravenously and about 15% reported using both heroin and cocaine (HC group) intravenously. Reported cocaine consumption was similar in the HC and C groups. Heroin was used on fewer days by the HC than by the H group, but the number of injections per day was similar. Speedball use, which was quantified independently from heroin and cocaine use, was reported almost exclusively by the HC group, and speedball was used less often than either heroin or cocaine alone. Finally, a similar proportion of individuals in the C and the HC groups consumed alcohol in the 24 hours preceding the interview, but a larger proportion of individuals in the HC group reported the use of marijuana. CONCLUSION: In a cohort of injection drug users in Montréal, cocaine was the most prevalent illicit drug. Furthermore, about 70% of the heroin users also injected cocaine, but not in the form of speedball. Thus, the sequential co-use of heroin and cocaine is highly prevalent in Montréal and deserves particular clinical attention.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".