Table 2.
Mixed-model repeated measures planned contrast test of group × measurement-occasion interaction from baseline to 12-month follow-up for all primary and secondary outcome measures.
| Outcome measure | Estimated marginal means (SE) | t test (df)a | P value | dinteraction (95% CI)b | d12 months (95% CI)c | ||
| Intervention | Control | ||||||
| Parenting to Reduce Adolescent Depression and Anxiety Scale | |||||||
| Baseline | 46.58 (0.57) | 47.88 (0.57) | —d | — | — | — | |
| 12 months | 51.68 (0.59) | 49.99 (0.61) | 4.81 (328.17) | <.001 | 0.51 (0.29 to 0.71) | 0.21 (−0.01 to 0.43) | |
| Parenting to Reduce Adolescent Depression and Anxiety Scale—Adolescent Report | |||||||
| Baseline | 24.44 (0.44) | 24.89 (0.43) | — | — | — | — | |
| 12 months | 23.38 (0.51) | 24.16 (0.50) | −0.59 (297.53) | .56 | −0.06 (−0.28 to 0.15) | −0.13 (−0.36 to 0.11) | |
| Spence Children’s Anxiety Scale—Parent Report | |||||||
| Baseline | 17.99 (0.90) | 18.51 (0.90) | — | — | — | — | |
| 12 months | 13.72 (0.95) | 15.64 (0.94) | −1.28 (321.37) | .20 | −0.14 (−0.37 to 0.08) | −0.12 (−0.34 to 0.10) | |
| Spence Children’s Anxiety Scale—Child Report | |||||||
| Baseline | 28.73 (1.36) | 30.20 (1.33) | — | — | — | — | |
| 12 months | 27.20 (1.52) | 26.56 (1.49) | 1.36 (294.14) | .18 | 0.16 (−0.07 to 0.39) | 0.04 (−0.19 to 0.27) | |
| Short Mood and Feelings Questionnaire—Parent Report | |||||||
| Baseline | 5.07 (0.40) | 4.75 (0.40) | — | — | — | — | |
| 12 months | 3.48 (0.40) | 4.21 (0.40) | −1.88 (329.02) | .06e | −0.21 (−0.42 to 0.01) | −0.14 (−0.36 to 0.08) | |
| Short Mood and Feelings Questionnaire—Child Report | |||||||
| Baseline | 6.16 (0.47) | 6.40 (0.46) | — | — | — | — | |
| 12 months | 7.06 (0.58) | 7.08 (0.57) | 0.33 (296.86) | 0.74 | 0.04 (−0.19 to 0.27) | −0.01 (−0.24 to 0.22) | |
at statistic of the planned contrast test of group × measurement-occasion interaction from baseline to 12-month follow-up, estimated under the group × measurement-occasion mixed model.
bCohen d effect size of the group × measurement-occasion interaction from baseline to 12-month follow-up, calculated based on the t statistic of the planned contrast. Negative effect size indicates greater reduction in scores from baseline to 12-month follow-up in the intervention group compared with the control group.
cCohen d effect size of the difference between groups at 12-month follow-up. Negative effect size indicates lower scores in the intervention group compared with the control group.
dNot applicable.
eBecomes statistically significant with square-root-transformed data: t(324.98)=−2.04; P=.04; d=−0.21 (95% CI −0.42 to −0.01).