Researchers from the Massachusetts Institute of Technology's Picower Institute for Learning and Memory say the new class of drugs -- such as rimonabant (trade name Acomplia) -- work by blocking the same receptor cells in the brain that bind to compounds found in marijuana. Known collectively as cannabinoids, the compounds are also produced naturally by the body.

The scientists said they found blocking cannabinoid receptors in laboratory mice suppressed the adaptive rewiring of the brain that is an essential task of maturation.

"Our finding of a profound disruption of cortical plasticity in juvenile mice suggests caution is advised in the use of such compounds in children," said Professor Mark Bear, lead author of the study.

The work is reported in the journal Neuron.