Tuesday, 30 April 2013

Classroom Interventions to Prevent Depression do Not Work

BMJ 2012;345:e6058.

It seems medical journals these days are more willing to publish articles which do not show a difference. One example of this is a cluster randomized trial of a cognitive behavioral program to prevent depression in adolescents delivered in schools in England. In this study the authors randomly allocated teenagers by school years to either receive the cognitive behavioral program; the usual curriculum for personal, social and health education supplemented by external experts; or the usual curriculum for personal, social and health education alone. 

The cognitive behavioral program consisted of nine modules and two booster sessions of 50-60 minutes each. After a year, in those at high risk of depression, there was no difference between the groups in depressive symptoms. This is disappointing but not inconsistent with other school intervention programs which although well intentioned may actually increase risky behaviors (for example suicide prevention programs in schools).

The paradox is that systematic reviews have come out in favor of school based prevention programs for depression but it seems that these analyses included studies that did not have “placebo” arms. This is clearly important in depression which has a high rate of spontaneous remission. 

So do you trust the single well done randomized controlled trial or the systematic review of studies with weaker methodology – a topic which will keep epidemiologists up at the bar late into the night. It remains somewhat baffling to me why health prevention programs in schools do not work – after all schools are all about learning new things. Any ideas?

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