Table 5.
Linear mixed effects model for the effect of group, site, stimulus type, and movement type on reaction times in the CAAT task.
| Model |
Model coefficients |
||||||
|---|---|---|---|---|---|---|---|
|
Fixed effects |
Random effects | ||||||
| B | 95 % CI (B) | SE (B) | t | p | SD | ||
| Intercept | 6.43 | 6.39: 6.47 | 0.02 | 322.67 | < 0.001 | 0.15369 | |
| Site: NL-TX | −0.09 | −0.15: −0.03 | 0.03 | −3.10 | 0.002 | ||
| Group: CAN-CON | −0.08 | −0.13: −0.02 | 0.03 | −2.53 | 0.012 | ||
| Movement: Approach-Avoid | 0.09 | 0.07: 0.11 | 0.01 | 8.17 | <0.001 | 0.06516 | |
| Stimulus: Cannabis - Neutral | 0.00 | −0.02: 0.01 | 0.01 | −0.23 | 0.816 | 0.0198 | |
| Site * Group | 0.15 | 0.06: 0.24 | 0.05 | 3.27 | 0.001 | ||
| Site * Movement | −0.04 | −0.07: 0 | 0.02 | −2.15 | 0.033 | ||
| Site * Stimulus | 0.01 | −0.01: 0.04 | 0.01 | 1.04 | 0.301 | ||
| Group * Movement | −0.01 | −0.05: 0.02 | 0.02 | −0.81 | 0.421 | ||
| Group * Stimulus | −0.02 | −0.04: 0 | 0.01 | −1.74 | 0.084 | ||
| Movement * Stimulus | −0.04 | −0.06: −0.02 | 0.01 | −3.45 | 0.001 | 0.02676 | |
| Site * Group * Movement | −0.02 | −0.07: 0.03 | 0.03 | −0.87 | 0.384 | ||
| Site * Group * Stimulus | −0.01 | −0.05: 0.02 | 0.02 | −0.66 | 0.513 | ||
| Site * Movement * Stimulus | 0.00 | −0.04: 0.03 | 0.02 | −0.21 | 0.832 | ||
| Group * Movement * Stimulus | 0.04 | 0.002: 0.07 | 0.02 | 2.13 | 0.034 | ||
| Site * Group * Movement * Stimulus | 0.02 | −0.03: 0.07 | 0.03 | 0.69 | 0.489 | ||
| Sensitivity Analysis | |||||||
| Intercept | 6.45 | 6.08: 6.82 | 0.19 | 33.95 | <0.001 | 0.15 | |
| Site: NL-TX | −0.11 | −0.19: −0.03 | 0.04 | −2.74 | 0.007 | ||
| Group: CAN-CON | −0.08 | −0.14: −0.01 | 0.03 | −2.38 | 0.02 | ||
| Movement: Approach-Avoid | 0.09 | 0.07: 0.11 | 0.01 | 8.01 | <0.001 | 0.07 | |
| Stimulus: Cannabis - Neutral | 0.00 | −0.02: 0.01 | 0.01 | −0.19 | 0.85 | 0.02 | |
| Site * Group | 0.12 | 0: 0.24 | 0.06 | 1.91 | 0.06 | ||
| Site * Movement | −0.04 | −0.08: 0 | 0.02 | −2.06 | 0.04 | ||
| Site * Stimulus | 0.02 | −0.01: 0.05 | 0.01 | 1.24 | 0.22 | ||
| Group * Movement | −0.02 | −0.05: 0.02 | 0.02 | −0.99 | 0.32 | ||
| Group * Stimulus | −0.02 | −0.04: 0 | 0.01 | −1.67 | 0.10 | ||
| Movement * Stimulus | −0.04 | −0.06: −0.02 | 0.01 | −3.36 | 0.001 | 0.03 | |
| Site * Group * Movement | −0.02 | −0.09: 0.05 | 0.03 | −0.58 | 0.56 | ||
| Site * Group * Stimulus | −0.04 | −0.09: 0.01 | 0.02 | −1.73 | 0.09 | ||
| Site * Movement * Stimulus | −0.01 | −0.05: 0.03 | 0.02 | −0.60 | 0.55 | ||
| Group * Movement * Stimulus | 0.03 | 0: 0.07 | 0.02 | 2.04 | 0.04 | ||
| Site * Group * Movement * Stimulus | 0.05 | −0.02: 0.12 | 0.03 | 1.40 | 0.16 | ||
| Covariates | Age | 0.00 | −0.01: 0.01 | 0.01 | −0.21 | 0.84 | |
| Gender (male) | −0.07 | −0.12: −0.02 | 0.03 | −2.65 | 0.009 | ||
| Gender (other) | −0.15 | −0.46: 0.15 | 0.16 | −0.97 | 0.34 | ||
| Education years | 0.00 | −0.01: 0.01 | 0.01 | −0.38 | 0.70 | ||
| AUDIT | 0.00 | −0.01: 0 | 0.00 | −0.84 | 0.40 | ||
| Lifetime illicit substance use | 0.00 | 0: 0 | 0.00 | 0.89 | 0.37 | ||
| CAAT accuracy (all trials) | 0.09 | −0.27: 0.46 | 0.19 | 0.51 | 0.61 | ||
Note. Linear mixed model results using random intercepts and restricted maximum likelihood estimation; CAN: cannabis group, CI: Confidence Interval (Wald), CON: control group, NL: Netherlands, SE: Standard Error, SD: Standard deviation, TX: Texas; CAN & NL were used as the reference categories. Significant results are presented in bold.