Data from Monitoring the Future revealed a decline in teen use of marijuana in 2014, as well as declines for alcohol and all drug use. This reduction for marijuana, which reverses a 5-year trend, is especially significant given the growing legality of weed and the decreasing negative perception of its use. “The belief that regular marijuana use harms the user continues to fall among youth, so changes in this belief do not seem to explain the change in use this year, as it has done over most of the life of the study,” Johnston said.

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