Seventy-three published and unpublished studies were included in the review. The total number of participants was not reported.
Education interventions (23 studies): there was no consistent increase or decrease in most of the outcomes measured. In ten of the 23 studies, the intervention was individualised and home-based. In those studies where they were assessed, dysphoric outcomes, depression and burden were found to be decreased while knowledge, coping and life satisfaction were increased.
Support and education interventions (14 studies): of the 59 outcome variables measured only 18 showed a statistically-significant improvement in 12 of the 14 studies. The most common benefits observed were decreased burden and depression with increased knowledge.
Counselling interventions (4 studies): only 2 of the 6 outcomes in one of the four studies showed a statistically-significant benefit.
Respite interventions (16 studies): there was a significant reduction in 33% of negative outcomes. The range of respite utilised in the different studies made it difficult to interpret the findings.
Case-management interventions (6 studies): only one study found a significant benefit in one outcome (stress). The poor result was possibly due to the patients finding this type of intervention to be inflexible to their needs.
Multi-component interventions (12 studies): mixed effects on both positive and negative consequences of caregiving were found. The rate of institutionalisation was reduced in two studies.
Overall, only 32% of the interventions had a significant beneficial effect. The studies suffered from: small sample sizes; lack of sample homogeneity; lack of intervention specificity; diversity in length, duration and intensity of specific intervention strategies; poor matches between intervention and outcomes; lack of pre-screening of caregivers for level of outcome variables; and a lack of attention to matching caregiver needs to intervention strategies.