Cognitive effects of heavy alcohol and marijuana use in adolescents

November, 2010

Alcohol and marijuana abuse associated with specific cognitive impairments in adolescents, but more surprisingly family history of substance abuse can also have an effect.

A study involving 48 adolescents, of whom 19 had been diagnosed with substance abuse/dependence, and 14 had a family history of substance abuse but no history of personal use, has found that greater alcohol use was associated with a significant decrease in attention and executive function (which is involved in planning and decision-making), while greater marijuana use was associated with poorer memory. Adolescents in the substance abuse group had lower scores in attention, memory, and processing speed, compared to the other groups, while those with a family history of abuse (but no personal history) had poorer visuospatial ability.

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