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Database search results.
| Database | Database provider | Years searched | Number of citations retrieved (n=1536) |
| MEDLINE | OVID | 1996 to March week 1, 2013 | 403 |
| PsycInfo | OVID | 1996 to March week 2, 2013 | 142 |
| Embase | OVID | 1996 to March week 3 2013 | 609 |
| MEDLINE | Pubmed | 1996 to March week 3, 2013 | 380 |
| Manual search | – |
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2 |
