Table 3.
Mixed effects model results for main effects of treatment, time, and interaction terms.
| Domain | Fixed effect | df1 | df2 | F | Reg. Coeff | Std. Error | p-value |
|---|---|---|---|---|---|---|---|
| Composite cognitive functioning | Treatment | 1 | 8 | 0.04 | −1.83 | 8.75 | 0.84 |
| Time | 1 | 18 | 26.08 | 0.90 | 0.18 | <0.01 | |
| Treatment*Time | 1 | 18 | 1.36 | −0.33 | 0.29 | 0.26 | |
| Speed of processing | Treatment | 1 | 8 | 0.42 | 6.26 | 9.68 | 0.54 |
| Time | 1 | 18 | 4.81 | 1.08 | 0.34 | 0.042 | |
| Treatment*Time | 1 | 18 | 3.40 | −0.99 | 0.54 | 0.082 | |
| Attention/vigilance | Treatment | 1 | 8 | 1.32 | −9.28 | 8.09 | 0.28 |
| Time | 1 | 18 | 6.76 | 0.67 | 0.33 | 0.018 | |
| Treatment*Time | 1 | 18 | 0.00 | 0.021 | 0.52 | 0.97 | |
| Working memory | Treatment | 1 | 8 | 0.15 | 3.50 | 8.89 | 0.70 |
| Time | 1 | 18 | 2.35 | 0.96 | 0.40 | 0.14 | |
| Treatment*Time | 1 | 18 | 2.35 | −0.96 | 0.62 | 0.14 | |
| Verbal learning | Treatment | 1 | 8 | 0.21 | −2.43 | 5.29 | 0.66 |
| Time | 1 | 18 | 3.08 | 0.083 | 0.34 | 0.096 | |
| Treatment*Time | 1 | 18 | 4.26 | −1.11 | 0.54 | 0.054 | |
| Visual learning | Treatment | 1 | 8 | 0.07 | −1.83 | 7.06 | 0.80 |
| Time | 1 | 18 | 1.99 | 0.17 | 0.44 | 0.18 | |
| Treatment*Time | 1 | 18 | 0.87 | 0.65 | 0.69 | 0.36 | |
| Reasoning & problem solving | Treatment | 1 | 8 | 0.31 | −4.17 | 7.49 | 0.59 |
| Time | 1 | 18 | 17.89 | 0.88 | 0.27 | <0.01 | |
| Treatment*Time | 1 | 18 | 0.02 | 0.063 | 0.43 | 0.89 | |
| Social cognition | Treatment | 1 | 8 | 0.07 | 1.28 | 4.68 | 0.79 |
| Time | 1 | 18 | 1.38 | 0.40 | 0.38 | 0.26 | |
| Treatment*Time | 1 | 18 | 0.02 | −0.083 | 0.60 | 0.89 | |
| PSQI | Treatment | 1 | 8 | 0.95 | 1.71 | 1.75 | 0.36 |
| Time | 1 | 73 | 78.16 | −0.35 | 0.093 | <0.01 | |
| Treatment*Time | 1 | 73 | 17.35 | −0.62 | 0.15 | <0.01 | |
| ESS | Treatment | 1 | 8 | 3.96 | 7.26 | 3.65 | 0.082 |
| Time | 1 | 74 | 6.48 | −0.12 | 0.14 | 0.013 | |
| Treatment*Time | 1 | 74 | 2.15 | −0.32 | 0.22 | 0.15 |
df1 = numerator degrees of freedom. df2 = denominator degrees of freedom. Reg. Coeff = partial regression coefficient estimate (i.e., effect size). For “Treatment” reg coeff represents the mean difference between treatment groups on the dependent variable with respect to the modafinil group. For “Time” reg coeff represents rate of change per week in study for the modafinil group. For “Treatment*Time” reg coeff represents the difference in rate of change between treatment groups with respect to the modafinil group as reference. Std. error = standard error of the partial regression coefficient estimate. Bold text indicates a significant or marginally significant effect.