Teen brain volume changes with small amount of cannabis use, study finds

by University of Vermont
Jan. 14, 2019

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Few studies have looked at the effects of the first few uses of a drug, says Garavan. Most researchers focus on heavy marijuana users later in life and compare them against non-users. These new findings identify an important new area of focus.

"Consuming just one or two joints seems to change gray matter volumes in these young adolescents," Garavan says.

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Exploiting the advantages of the study's longitudinal data, the researchers ruled out the likelihood that the cannabis-using kids had pre-existing differences in gray matter thickness or that they had specific personality traits that might correlate with the difference in brain makeup.

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Typically at that age, Garavan says, the adolescent brain undergoes a "pruning" process, where it gets thinner, rather than thicker as it refines its synaptic connections.

"One possibility is they've actually disrupted that pruning process," Garavan says of the marijuana-using kids.

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tags: drug use, drug abuse