Table 2.
Analyses of the effects of cannabis use on the neuropsychological performance domains
| Outcome variables a | k c | m d | n e CU f | n CNU g | β h (SE) i | 95% CI j | t (df) k | p l |
|---|---|---|---|---|---|---|---|---|
| Overall | 7 | 78 | 304 | 369 | −0.009 (0.155) | (−0.389, 0.372) | −0.06 (6.54) | 0.957 |
| Attention | 3 | 8 | 107 | 211 | −0.350 (0.806) | (−2.262, 1.561) | −0.43 (6.90) | 0.677 |
| Executive function | 6 | 28 | 292 | 342 | 0.165 (0.283) | (−0.618, 0.949) | 0.58 (4.06) | 0.591 |
| Premorbid IQ b | 4 | 4 | 232 | 188 | 0.097 (0.248) | (−0.692, 0.886) | 0.39 (3) | 0.721 |
| Processing speed | 2 | 3 | 106 | 83 | 0.150 (0.280) | (−3.408, 3.708) | 0.53 (1) | 0.687 |
| Verbal memory and learning | 5 | 14 | 215 | 220 | −0.005 (0.183) | (−0.400, 0.389) | −0.03 (13) | 0.977 |
| Visual memory | 3 | 7 | 118 | 110 | −0.076 (0.244) | (−1.138, 0.984) | −0.31 (1.98) | 0.783 |
| Working memory | 6 | 10 | 292 | 342 | −0.037 (0.295) | (−0.800, 0.725) | −0.13 (4.92) | 0.904 |
a
For motor coordination and current IQ, there were not enough observations to perform the analyses.
b
For premorbid IQ, a standard two-level random effects model was applied because there was only one outcome per study.
c
k: number of studies that report information about the moderator variable.
d
m: number of effect sizes that report information about the moderator variable.
e
n: sample size.
f
CU: cannabis user group.
g
CNU: cannabis nonuser group.
h
β: mean effect size.
i
SE: standard error.
j
CI: confidence interval.
k
df: degrees of freedom.
l
p: significant p value (p ≤ 0.005).