Table 2.
Databases searched
| Cochrane Central Register of Controlled Trial |
| Current Controlled trials |
| ClinicalTrials.gov |
| MEDLINE |
| EMBASE |
| PsycINFO |
| CINAHL (Cumulative Index to Nursing and Allied Health Literature) |
| SIGLE (Grey Literature in Europe) |
| ISTP (Index to Scientific and Technical Proceedings) |
| INSIDE (BL database of Conference Proceedings and Journals) |
| Aslib Index to Theses (UK and Ireland theses) |
| Dissertation Abstract (USA) |
| ADEAR (Alzheimer's Disease Clinical Trials Database) |
| Alzheimer Society |
| South Australian Network for Research on Ageing |
| US Dept of Veterans Affairs Cooperative Studies |
| National Institutes of Health (NIH) |
| GlaxoSmithKline |
| Schering Health Care Ltd |
| Hong Kong Health Services Research Fund |
| Medical Research Council (MRC) |
| National Research Register |
| NHS R&D Health Technology Assessment Programme |
| LILACS:Latin American and Carribbean Health Science Literature |