Table 2.
Results of the ratings of selected THC side-effects acquired by means of visual analog scales (range, 0–100) before administration of the medication (‘Baseline’) and 2 h after drug administration (‘Post’)
| Repeated-measures ANOVA effects in a 2 × 2 design | Differences from baseline, THC vs. placebo | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Measure (mm VAS) | Drug | Measurement | Mean | SD | ‘Drug’ | ‘Measurement’ | ‘Drug’ by ‘measurement’ | ‘Gender’* | Mean | 95% CI, lower limit | 95% CI, upper limit | Student's paired t test, P value |
| Drowsiness | Placebo | Baseline | 5.8 | 14.7 | d.f. = 1,13, | d.f. = 1,13, | d.f. = 1,13, | d.f. = 1,13, | 57.3 | 36.0 | 78.7 | 0 |
| Post | 2.3 | 4.7 | F = 47.239, | F = 19.269, | F = 55.14, | F = 0.05, | ||||||
| THC | Baseline | 6.0 | 13.1 | P < 0.001† | P = 0.001† | P = 0.001† | P = 0.826 | |||||
| Post | 59.5 | 28.2 | ||||||||||
| Tiredness | Placebo | Baseline | 51.5 | 23.3 | d.f. = 1,13, F = 7.787, P = 0.015† | d.f. = 1,13, F = 1.978, P = 0.183 | d.f. = 1,13, F = 9.809, P = 0.008† | d.f. = 1,13, F = 0.636, P = 0.44 | 24.9 | 7.6 | 42.2 | 0.008 |
| Post | 43.5 | 25.1 | ||||||||||
| THC | Baseline | 51.3 | 19.1 | |||||||||
| Post | 68.3 | 17.5 | ||||||||||
| Nausea | Placebo | Baseline | 1.8 | 5.1 | d.f. = 1,13, F = 4.958, P = 0.044† | d.f. = 1,13, F = 2.804, P = 0.118 | d.f. = 1,13, F = 4.326, P = 0.058 | d.f. = 1,13, F = 0.83, P = 0.777 | 13.7 | 0.2 | 27.3 | 0.047 |
| Post | 0.5 | 0.9 | ||||||||||
| THC | Baseline | 1.9 | 4.9 | |||||||||
| Post | 14.3 | 24.1 | ||||||||||
| Euphoria | Placebo | Baseline | 16.7 | 26.4 | d.f. = 1,13, F = 1.259, P = 0.282 | d.f. = 1,13, F = 2.116, P = 0.169 | d.f. = 1,13, F = 3.507, P = 0.084 | d.f. = 1,13, F = 0.668, P = 0.428 | 16.3 | −1.7 | 34.3 | 0.072 |
| Post | 13.0 | 21.4 | ||||||||||
| THC | Baseline | 12.9 | 19.2 | |||||||||
| Post | 25.6 | 23.1 | ||||||||||
Abbreviations are as follows: CI, confidence interval; TDI, threshold, discrimination, identification; THC, Δ9-tetrahydrocannabinol; VAS, visual analog scale. Statistical analysis results are shown for the repeated-measures ANOVA in a 2 × 2 design (two measurements per day, two medications) and, in addition, as comparisons between the THC and placebo conditions for the respective differences from baseline.
Given that no effects of ‘gender’ were identified, the interactions including this factor, all having resulted in nonsignificant effects, are omitted from this table.
Significant effect (P < 0.05).