Targeted interventions for those at risk for depression have greater effect than universal interventions

Depression among youth is a growing public health concern, affecting one to two percent of elementary school-aged children and three to eight percent of adolescents.

To determine what programs are effective in preventing depressive symptoms, researchers from Vanderbilt University conducted a meta-analysis of the last 20 years of research on interventions aimed at preventing depressive symptoms in youth.

The results of the study appearing in the June issue of the Journal of Consulting and Clinical Psychology, published by the American Psychological Association (APA), showed that targeted interventions for those at risk for depression have greater effect sizes than universal interventions.

Thirty studies were reviewed on how well different intervention programs worked in preventing depressive symptoms among children and adolescents. Three different types of interventions were examined: universal, selective, and indicated programs, said researchers Jason L. Horowitz, MS, and Judy Garber, PhD, of Vanderbilt University. Universal preventive interventions are provided to all members of a particular population. Selective prevention programs are used for members of a subgroup of a population whose risk is considered above average. Finally, indicated preventive interventions are for individuals who show early signs or symptoms of a psychological disorder.

According to the findings of the meta-analysis, both selective and indicated prevention programs had greater effect sizes than universal programs in alleviating depressive symptoms at post-intervention and at a six-month follow up. This may have been due to the fact that very large samples are needed to show an effect in studies using universal samples. That is, it is not necessarily that universal programs are not effective, but that studies may not have had the power to detect significant effects. Moreover, universal programs, which often are conducted in schools in large group formats, do a good job at avoiding the stigma of singling out individuals for intervention, do not require prescreening, and have a relatively low dropout rate.

In contrast, Horowitz and Garber showed that selective programs, which target individuals who are more at risk for depression because of exposure to such factors as parental divorce, deaths, parental depression or alcoholism, or poverty, produced a significantly larger effect size in reducing depressive symptoms compared to universal programs. Selective programs usually involve a more diverse sample, are more varied in their delivery of information, and target other outcomes besides depression (e.g. academic improvement, parent-child relationship).

Indicated programs, which are used for individuals who are already showing signs and symptoms of depression and are at increased risk of experiencing clinical depression, also showed a significantly greater effect size than universal programs, said Horowitz and Garber. Like selective programs, indicated programs typically use small group format, teach cognitive techniques that emphasize reducing negative thinking, increase problem-solving skills and goal setting, and show participants how to look at events from another perspective.

Age and gender also moderated the effect of the interventions on reducing depressive symptoms. Older female adolescents who participated in an intervention were more likely to have lower levels of symptoms at post-intervention.

The authors also highlighted the distinction between treatment and prevention effects, and showed that the studies reviewed in the meta-analysis appeared to be more effective in reducing symptoms of depression (i.e., treatment) rather than in preventing the worsening of depressive symptoms. Only 4 of the 30 studies showed evidence of an actual prevention effect.

To design better prevention programs for children and adolescents, said Horowitz and Garber, future studies should focus on targeted populations that include female adolescents, offspring of depressed parents, youth with elevated depression and/or anxiety symptoms themselves, and youth who have been exposed to stressors, such as parental psychopathology, divorce, or death. Studies also should have longer follow up evaluations to measure whether a preventive effect occurred.