Table 2.
Risk of bias across the included studies.
| Study | Selection bias Random sequence generation |
Selection bias Allocation concealment |
Reporting bias Selective reporting |
Detection bias Blinding (outcome assessment) |
Attrition bias Incomplete outcome data |
Other bias Inclusion of a comparator |
|---|---|---|---|---|---|---|
| 1. ⁎Allen et al. (2016) | Low | Low | Low | High | Low | Low |
| 2. ⁎Bergström et al. (2010) | Low | Low | Unclear | Low | Low | High |
| 3. ⁎Carlbring et al. (2001) | Unclear | Low | Unclear | Low | Low | Low |
| 4. ⁎Carlbring et al. (2005) | Low | Unclear | Unclear | Low | Low | High |
| 5. ⁎Carlbring et al. (2006) | Low | Unclear | Unclear | Low | Low | Low |
| 6. ⁎Carlbring et al. (2003) | Low | Unclear | Low | High | Low | High |
| 7. ⁎Ciuca et al. (2018) | Low | Low | Low | Low | Low | Low |
| 8. ⁎Fogliati et al. (2016) | Low | Low | Low | High | Low | Low |
| 9. ⁎Kiropoulos et al. (2008) | Low | Unclear | Unclear | Unclear | Low | Low |
| 10. ⁎Klein et al. (2009) | Low | Low | Unclear | Low | Low | High |
| 11. ⁎Klein et al. (2006) | Unclear | Low | Unclear | Unclear | Low | Low |
| 12. ⁎Richards et al. (2006) | Unclear | Unclear | Unclear | Low | Low | Low |
| 13. ⁎Wims et al. (2010) | Low | Low | High | High | Low | Low |
Note: low = low risk of bias; high = high risk of bias; unclear = unclear risk of bias; N = no; Y = yes.