Eleven studies (n=1,113) were included in the review. Random assignment to treatment occurred in 10 studies. There were 14 comparisons of CBT and non-CBT interventions; six studies had a no-treatment control group. The mean total attrition was 18.9%.
Overall, the CBT-based interventions were shown to provide greater overall benefit than non-CBT interventions both at post-treatment (aggregated effect size 0.27, 95% CI 0.09 to 0.44; nine studies) and after follow-up (aggregated effect size 0.25, 95% CI 0.05 to 0.46). When the results were adjusted for researcher allegiance, there were no significant differences in the effectiveness of the interventions. CBT-based interventions were also found to elicit statistically significant overall benefits compared with no-treatment control groups immediately post-treatment (aggregate effect size 0.38, 95% CI 0.09 to 0.67), but the differences between groups was not significant at follow-up.
Significant benefits were found with CBT-based therapies compared witho non-CBT intervention groups for the five domains of grief (four studies), depression (five studies), anxiety (five studies), trauma (two studies) and general distress (five studies) at post-treatment, but by the end of the follow-up period the differences between groups remained significant only for the outcomes depression (three studies) and anxiety (three studies).
Compared with no-treatment control groups significant differences were observed in favour of CBT-based treatment for the domains depression (three studies), anxiety (three studies) and trauma (two studies) at post-treatment, but there were no differences between the groups at follow-up.
There was no statistically significant heterogeneity reported between effect sizes at post-treatment or follow-up.