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    Is marijuana safer than alcohol, or vice versa? Each substance has different effects on the body. Here's how the two compare. In most cases, these effects have been studied in heavy, chronic smokers and drinkers, not occasional users.
    Marijuana Alcohol
    Immediate Effects
    • Impairs judgment
    • Slows reaction time
    • Affects coordination and motor skills
    • Increases risk for accidents
    • Changes behavior and mood
    • Impairs judgment
    • Slows reaction time
    • Affects coordination and motor skills
    • Increases risk for accidents
    • Changes behavior and mood
    Brain
    • Reduces blood flow to brain
    • Interferes with learning, memory, and attention
    • May increase risks for schizophrenia and other mental illnesses
    • May contribute to anxiety and depression
    Cancer
    • Linked to precancerous lung changes
    • May increase testicular cancer risk in young men
    May increase risks of these cancers:
    • Breast
    • Esophagus
    • Liver
    • Throat
    Driving
    • Impairs judgment
    • Slows reaction time
    • Affects coordination and motor skills
    • Increases risk for accidents
    • Impairs judgment
    • Slows reaction time
    • Affects coordination and motor skills
    • Increases risk for accidents
    Liver
    • No known effects
    Increases risks for:
    • Fatty liver disease
    • Alcoholic hepatitis
    • Cirrhosis
    Lungs
    • Contributes to precancerous lung changes
    • May lead to more coughing and wheezing
    • May damage lungs
    Pregnancy
    • May lead to low birth weight
    • May lead to developmental and behavior problems in baby
    • No evidence it causes birth defects
    Increases risks for:
    • Miscarriage
    • Preterm birth
    • Stillbirth
    • Birth defects
    • Low birth weight
    • Learning and behavior problems

    Reviewed by Michael W. Smith, MD on February 18, 2014

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