| Database | Frequency of search |
| MEDLINE (Ovid) | weekly |
| EMBASE (Ovid) | weekly |
| CENTRAL (The Cochrane Library) | Quarterly (4 issues per year) |
| PsycINFO (Ovid) | Monthly |
| CINAHL (Ebsco) | Monthly |
| AMED (Ebsco) | Monthly |
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