Seven randomised controlled trials and one controlled clinical trial were included (n=742, range 20 to 193).
Three studies assessed cognitive development in children (n=419): two were rated as moderate quality and one as strong quality. One study showed short-term beneficial effects on cognitive development in children, but found none for long-term benefit in emotional and behavioural adjustment or cognitive development after five years of follow-up. Results for the remaining study were mixed.
Five studies (six papers) assessed mother-infant interaction or relationship (n=323), all rated as of moderate quality. The five studies reported that an improvement regardless of the intervention or target population, though there are uncertainties surrounding the outcome measures used.
Clinical and methodological heterogeneity were evident with respect to interventions, populations and outcome measures.