If they perform badly on a test, they will find some way to blame the negative outcome on factors external to themselves, or to focus on their successes and not their failures. Low self-esteem individuals, however, do exactly the opposite. If they are presented with a good outcome they will find some factor in the environment to blame it on, while claiming that bad outcomes are entirely their fault and that they bear the full responsibility of the blame. The second fact is that low self esteem individuals tend to do very poorly on a second task after intially failing a first one. Much more so than high self esteem individuals.
Failure tends to beget more failure when one has low self esteem.
The problem with DARE is largely with its effects on low self-esteem children who arguably are at the most risk for drug abuse. Those high in self-esteem will of course have their perceptions of themselves reinforced. They are, arguably, only ever going to wind up as casual drug users, and these programs will probably prevent this from happening. However, the message to the low self-esteem children reinforces their beliefs that if they use drugs they are taking actions entirely as an individual agent which are morally reprehensible. Thus explaning the increased rate of marijuana use among DARE graduates.