After the first studies were conducted in the 1990’s, the number of studies has increased rapidly since 2000.
A recent meta-analysis of these studies (van Zoonen et al., 2014) found a total of thirty-two studies in which subjects with a depressive disorder according to DSM-criteria at baseline were excluded, and only subjects with no formal depressive disorder were included.
Overall Effects of Depression Prevention Programs
In all these studies, it was examined whether the incidence rate of mental disorders was reduced in the recipients of preventive interventions compared to subjects who did not participate in such an intervention. The overall incidence rate ratio was 0.79 (95% CI: 0.69~0.91). The incidence rate ratio is the incidence rate of developing a depressive disorder in experimental subjects relative to the incidence rate in control subjects. An incidence rate ratio of 0.79 indicates a reduction of the risk of developing a depressive disorder in the next year of about 21% compared to people in the control groups. This study indicates that prevention of new cases of depressive disorders seems to be possible and may have become a realistic strategy to reduce the enormous burden of these disorders, next to treatment of existing depressive disorders.
Since then, even more randomized trials have shown that preventive interventions are effective in reducing the incidence of depressive disorders.