Prevalence of opium use and use disorder in the Iranian population: A systematic review and meta-analysis

Background and aims: Despite historical and cultural roots, there is limited comprehensive data on the prevalence of opium use and use disorder across the Iranian population. We systematically reviewed the prevalence and trends of opium use and use disorder in Iran. Method: Systematic review and meta-analysis adhering to PRISMA guidelines, including studies from 1990 to 2023 across the Iranian general population, university students, the young population and specific populations. Measurements included the prevalence of opium use and use disorder by sex, time indicators (lifetime, last 12 months, last month/current, current daily or almost daily), study year and population subgroups. Results: A total of 115 studies were included. Pooled prevalence of last 12-month opium use among the general population was 8.4% [95% confidence interval (CI) = 5.1–12.6%, studies = 6, n = 9302, I² = 97.2%] in men and 1.1% (95% CI = 0.4–2.3%, studies = 7, n = 13 129, I² = 95.1%) in women. The prevalence of the last 12-month opium use disorder was 3.7% (95% CI = 1.6–6.5%, studies = 3, n = 9605, I² = 97.7%) and 0.4% (95% CI = 0.1–0.8%, studies = 3, n = 10 465, I² = 81.0%) among male and female Iranian general population, respectively. Last 12-month opium use was 2.3% (95% CI = 1.5–3.3%, studies = 13, n = 37 164, I² = 83.3%) in male and 0.6% (95% CI = 0.2–1.0%, studies = 13, n = 43 471, I² = 85.4%) in female university students. Among male university students, lifetime opium use declined by 9.1 percentage points between 2000 and 2018 (95% CI = −18.6 to 0.4), while current daily or almost daily use decreased by 8.6 percentage points over the same period (95% CI = −11.8 to −5.3). Conclusions: Despite global shifts to harder opioids, opium use continues to have a very high prevalence among the Iranian general population. While the overall prevalence appears stable, younger generations have shown a declining use pattern.