Comparison between self-reported intake and laboratory detection of z-hypnotics, opioids, benzodiazepines and illicit drugs at the Oslo site
| Laboratory analysis | No | Yes | Not sure | |
| Self-reported intake of sleeping medication in last 24 hours | ||||
| Z-hypnotics | p<0.0001 | |||
| Negative | 2066 (87.2 %) | 291 (12.3 %) | 12 (0.5 %) | |
| Positive | 40 (24.2 %) | 125 (75.8 %) | 0 (0 %) | |
| Self-reported intake of painkillers in last 24 hours | ||||
| Opioids | p<0.0001 | |||
| Negative | 1875 (92.4 %) | 135 (6.6 %) | 19 (0.9 %) | |
| Positive | 178 (36.7 %) | 304 (62.5 %) | 4 (0.8 %) | |
| Self-reported intake of sedatives in last 24 hours | ||||
| Benzodiazepines | p<0.0001 | |||
| Negative | 1984 (96.2 %) | 63 (3.1 %) | 15 (0.7 %) | |
| Positive | 226 (49.6 %) | 223 (48.9 %) | 7 (1.5 %) | |
| Self-reported intake of illicit drugs in last 24 hours | ||||
| Illicit drugs | p<0.0001 | |||
| Negative | 2344 (98.7 %) | 28 (1.2 %) | 3 (0.1 %) | |
| Positive | 82 (50.0 %) | 81 (49.4 %) | 1 (0.6 %) | |