| Study | Reason for exclusion |
|---|---|
| Campbell 1993 | This controlled trial was not randomised. |
| Klerman 2001 | This is a study of the response of the circadian system of older adults, and is not a randomised trial. |
| Murphy 1996 | This controlled trial assigned participants to treatment on an alternating basis. |
| Rosenthal 1990 | No age or gender given for participants in this randomised controlled trial. |
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