TABLE 4.
Association of years of frequent cannabis use (at least twice a week) with IQ changes in a subsample of cannabis users (n = 1114).
| Unadjusted | Model 1 a | Model 2 b | Model 3 c | Model 4 d | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| b [95% CI] e | R 2 | p value | b [95% CI] e | R 2 | p value | b [95% CI] e | R 2 | p value | b [95% CI] e | R 2 | p value | b [95% CI] e | R 2 | p value | |
| Years of frequent cannabis use | 0.000 | 0.202 | 0.213 | 0.208 | 0.217 | ||||||||||
| No frequent use (n = 872) | Ref. | — | Ref. | — | Ref. | — | Ref. | — | Ref. | — | |||||
| ≤ 10 years (n = 112) | 0.30 [−1.55, 2.15] | 0.749 | 0.63 [−1.04, 2.30] | 0.458 | 0.46 [−1.24, 2.16] | 0.598 | 0.86 [−0.81, 2.53] | 0.310 | 0.59 [−1.11, 2.29] | 0.497 | |||||
| > 10 years (n = 130) | 1.20 [−0.54, 2.93] | 0.175 | 0.49 [−1.07, 2.06] | 0.537 | 0.43 [−1.28, 2.14] | 0.620 | 0.86 [−0.72, 2.44] | 0.287 | 0.59 [−1.12, 2.30] | 0.501 | |||||
a
Model 1: Age at follow‐up, retest interval, IQ at conscription, years of education.
b
Model 2: Age at follow‐up, retest interval, IQ at conscription, years of education, years of weekly extreme binge drinking, use of other illicit drugs, smoking.
c
Model 3: Age at follow‐up, retest interval, IQ at conscription, years of education, psychiatric disorders, CCI.
d
Model 4: Fully adjusted model.
e
Positive numbers indicate less change in IQ scores from baseline to follow‐up compared to the change observed in the reference group, while negative numbers indicate a larger change in IQ scores compared to the reference group.