Table 4.
Mean differences between contrast sensitivity conditions for all spatial frequencies.
| Spatial frequencies (cpd) | Group 1 (N = 10) (mean (SD)) |
Group 2 (N = 21) (mean (SD)) |
z | p value |
|---|---|---|---|---|
| 0.75 | 3.80 (12.02) | 23.00 (33.62) | − 1.666 | 0.19 |
| 1.5 | 0.00 (0.00) | 7.14 (17.93) | − 1.237 | 0.55 |
| 3 | − 5.00 (15.81) | 2.14 (36.90) | − 0.307 | 0.85 |
| 6 | 15.00 (47.43) | 21.90 (65.64) | − 0.203 | 0.85 |
| 12 | 20.80 (34.93) | 39.76 (52.28) | − 1.240 | 0.23 |
| 18 | − 9.20 (15.54) | 8.48 (19.14) | − 2.390 | 0.017 |
A positive value corresponds to worsened contrast sensitivity after smoking cannabis.
Mann–Whitney U test was applied for comparisons.