There were 128 studies included in the review (8,404 participants). Ninety-five studies were randomised controlled trials and the same number were published studies. Eighty-two studies assessed reminiscence, 37 assessed life-review and only 18 used life-review therapy. Follow-up data were reported in only 27 studies; mean length of follow up was 23 weeks (range two to 156 weeks). The results of the quality assessment were not reported but the authors stated that study quality did not affect the size of treatment effects.
The largest benefit of interventions using reminiscence (measured by pooled effect size) was found for the outcome of ego-integrity (g=0.64). Significant benefits were found for depression (g=0.57), purpose in life (g=0.48), preparation for death (g=0.40), mastery (g=0.40), mental health other than depression (g=0.33), positive well-being (g=0.33), social integration (g=0.31) and cognitive performance (g=0.24). Follow-up data indicated persistence of the effects for six of the nine outcomes (depression, other mental health measures, positive well-being, ego-integrity, cognitive performance and preparation for death).
Trim-and-fill analysis did not identify a consistent pattern of over-estimation. There was heterogeneity in most analyses; only preparation for death and cognitive performance showed homogeneity. Exploration of potential moderating variables suggested that benefits in depression and well-being were greatest in studies that used the most intensive intervention (life-review therapy). Improvements in depression were greater in participants who had depression or chronic physical health problems at baseline. Stronger effects were seen in studies without an active control. Results of multiple linear regression were reported.