Variables to be extracted for moderation analysis (where available, see supplementary material 3 for detailed variable categories and levels)
| Source characteristics | Sample characteristics | Design characteristics | Intervention characteristics |
| Publication status | Age | Method of recruitment | Size of the effect on sleep |
| Publication year | Gender | Nature of comparison group(s) | Duration |
| Journal impact factor | Type of mental health problem(s) | Attrition/dropout rate | Theoretical basis |
| Type of sleep problem(s) | Timing of follow-up | Mode of delivery | |
| Clinical status of mental health | Nature of outcome measure(s) | Adherence | |
| Clinical status of sleep problem | Type of analysis | ||
| Comorbidity | Adjusted versus unadjusted data | ||
| Concurrent medication use | Study quality | ||
| Concurrent psychological help |