Databases searched during the preparation of the review
| MEDLINE via OVID SP |
| Embase via OVID SP |
| CINAHL via OVID SP |
| British Nursing Index via OVID SP |
| PsycINFO via OVID SP |
| ASSIA via CSA |
| Cochrane–CDSR via Wiley |
| Cochrane–DARE via Wiley |
| Cochrane–Central via Wiley |
| Cochrane–HTA via Wiley |
| Social Care Online |
| Science and Social Science Citation Indices via Web of Knowledge |
| EconLit via OVID SP |
| Cochrane–NHS EED via Wiley |