Associations between misuse of prescription medications and use of non-prescription substances among US young adults aged 18–25 years, National Survey of Drug Use and Health, 2015–2018
| Opioid misuse* | Stimulant misuse* | Tranquilliser misuse* | Sedative misuse* | |
| APR (95% CI) | APR (95% CI) | APR (95% CI) | APR (95% CI) | |
| Recency—alcohol | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 1.55 (1.24 to 1.94) | 3.28 (2.16 to 4.98) | 1.40 (0.99 to 1.98) | 0.83 (0.39 to 1.75) |
| Used in the past 31 days to 12 months | 1.51 (1.20 to 1.90) | 2.07 (1.35 to 3.17) | 1.39 (0.98 to 1.97) | 0.95 (0.44 to 2.04) |
| Used in the >12 months | 1.47 (1.13 to 1.92) | 1.29 (0.78 to 2.14) | 1.33 (0.89 to 1.99) | 1.21 (0.48 to 3.07) |
| Recency—cigarettes | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 1.60 (1.41 to 1.82) | 1.37 (1.21 to 1.56) | 1.92 (1.61 to 2.30) | 0.97 (0.63 to 1.50) |
| Used in the past 31 days to 12 months | 1.34 (1.14 to 1.57) | 1.26 (1.09 to 1.46) | 1.77 (1.45 to 2.16) | 0.80 (0.47 to 1.37) |
| Used in the >12 months | 1.16 (0.99 to 1.33) | 1.16 (1.02 to 1.33) | 1.40 (1.15 to 1.69) | 0.77 (0.46 to 1.29) |
| Recency—cigars | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 1.20 (1.08 to 1.34) | 1.28 (1.15 to 1.43) | 1.22 (1.09 to 1.38) | 1.49 (1.00 to 2.22) |
| Used in the past 31 days to 12 months | 1.03 (0.91 to 1.15) | 1.45 (1.29 to 1.62) | 1.08 (0.94 to 1.23) | 1.83 (1.21 to 2.77) |
| Used in the >12 months | 1.04 (0.94 to 1.15) | 1.23 (1.11 to 1.36) | 0.95 (0.84 to 1.07) | 1.24 (0.87 to 1.78) |
| Recency—marijuana | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 2.99 (2.55 to 3.50) | 5.37 (4.38 to 6.58) | 5.81 (4.45 to 7.59) | 5.25 (2.91 to 9.47) |
| Used in the past 31 days to 12 months | 2.51 (2.14 to 2.95) | 5.10 (4.16 to 6.24) | 4.61 (3.52 to 6.02) | 3.14 (1.79 to 5.50) |
| Used in the >12 months | 1.77 (1.50 to 2.09) | 2.74 (2.22 to 3.38) | 2.75 (2.09 to 3.61) | 2.85 (1.55 to 5.24) |
| Recency—cocaine | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 1.81 (1.56 to 2.10) | 2.08 (1.80 to 2.39) | 2.79 (2.38 to 3.27) | 1.45 (0.85 to 2.47) |
| Used in the past 31 days to 12 months | 1.76 (1.56 to 1.99) | 2.04 (1.82 to 2.29) | 2.55 (2.23 to 2.93) | 1.49 (0.97 to 2.29) |
| Used in the >12 months | 1.52 (1.35 to 1.71) | 1.46 (1.29 to 1.64) | 1.66 (1.44 to 1.91) | 1.06 (0.69 to 1.63) |
| Recency—heroin | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 6.17 (2.10 to 14.29) | 0.77 (0.49 to 1.22) | 1.45 (1.20 to 1.76) | 3.13 (1.46 to 6.70) |
| Used in the past 31 days to 12 months | 7.21 (3.48 to 13.34) | 1.15 (0.90 to 1.48) | 1.53 (1.26 to 1.86) | 3.52 (1.91 to 6.47) |
| Used in the >12 months | 1.48 (1.06 to 2.03) | 0.98 (0.79 to 1.21) | 1.18 (1.00 to 1.40) | 1.85 (1.03 to 3.31) |
| Recency—inhalant | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 1.62 (1.26 to 2.08) | 1.27 (0.99 to 1.62) | 1.56 (1.22 to 2.00) | 2.80 (1.35 to 5.84) |
| Used in the past 31 days to 12 months | 1.32 (1.12 to 1.55) | 1.41 (1.21 to 1.64) | 1.38 (1.15 to 1.64) | 2.20 (1.29 to 3.74) |
| Used in the >12 months | 1.59 (1.45 to 1.74) | 1.17 (1.06 to 1.29) | 1.44 (1.30 to 1.59) | 2.01 (1.47 to 2.76) |
| Recency—hallucinogen | ||||
| Never used | Ref. | Ref. | Ref. | Ref. |
| Used in the past 30 days | 2.09 (1.78 to 2.45) | 2.15 (1.86 to 2.49) | 2.35 (1.96 to 2.82) | 2.72 (1.56 to 4.73) |
| Used in the past 31 days to 2 months | 1.85 (1.63 to 2.09) | 1.86 (1.64 to 2.11) | 2.26 (1.94 to 2.64) | 2.63 (1.67 to 4.15) |
| Used in the >12 months | 1.66 (1.48 to 1.86) | 1.37 (1.23 to 1.53) | 1.88 (1.63 to 2.16) | 1.70 (1.14 to 2.55) |
| Number of non-prescription behavioural used (past 30 days) | ||||
| None | Ref. | Ref. | Ref. | Ref. |
| 1 | 1.97 (1.70 to 2.28) | 4.66 (3.77 to 5.77) | 3.00 (2.37 to 3.79) | 1.41 (0.82 to 2.42) |
| 2 | 4.35 (3.78 to 5.00) | 12.04 (9.79 to 14.8) | 8.69 (6.94 to 10.89) | 5.04 (3.04 to 8.35) |
| 3 | 7.83 (6.80 to 9.02) | 19.78 (16.05 to 24.39) | 16.8 (13.43 to 21.01) | 9.24 (5.67 to 15.08) |
| 4 | 12.07 (10.37 to 14.05) | 31.82 (25.58 to 39.57) | 28.67 (22.74 to 36.16) | 10.69 (5.80 to 19.71) |
| 5+ | 18.02 (15.07 to 21.56) | 44.52 (35.17 to 56.36) | 48.41 (37.88 to 61.85) | 23.37 (12.16 to 44.91) |
| Number of non-prescription substances† used (past 12 months) | ||||
| None | Ref. | Ref. | Ref. | Ref. |
| 1 | 1.69 (1.37 to 2.09) | 4.87 (3.13 to 7.58) | 2.72 (1.81 to 4.08) | 1.20 (0.53 to 2.72) |
| 2 | 3.44 (2.81 to 4.19) | 16.97 (11.05 to 26.06) | 7.90 (5.35 to 11.68) | 2.24 (1.01 to 4.97) |
| 3 | 6.82 (5.62 to 8.28) | 31.44 (20.51 to 48.20) | 19.25 (13.12 to 28.23) | 5.41 (2.49 to 11.79) |
| 4 | 10.60 (8.72 to 12.89) | 58.15 (37.97 to 89.05) | 35.75 (24.41 to 52.36) | 9.04 (4.20 to 19.45) |
| 5+ | 20.60 (17.03 to 24.90) | 104.25 (68.18 to 159.39) | 80.98 (55.45 to 118.24) | 23.03 (10.7 to 49.55) |
Estimates in bold type indicate statistically significant differences within the demographic subgroup.
Non-prescription substances include alcohol, cigarettes, cigars, marijuana, cocaine, heroin, inhalants and hallucinogens.
*Misuse was defined as a report by the respondent that they had used the psychoactive prescription medication in the past year in any way not directed or prescribed, including use without a prescription of individual’s own, or deviations in the dose (greater amounts), frequency (more often) or duration (longer).
†Nonprescription substances include alcohol, cigarettes, cigars,marijuana, cocaine, heroin, inhalants, and hallucinogens
APR, adjusted prevalence ratio; Ref, Referent.