Table 1.

Summary of Longitudinal Human Studies Evaluating Effect of Prenatal Marijuana Use on Neurobehavioral Outcomes

Study Setting	Population	Major Findings1,50
Ottawa Prenatal Prospective Study (N=698)51 Ottawa, Canada 1978	Middle-income, predominantly Caucasian	-Under age 4 years: no differences in behavior, intellect, visual perception, language, attention or memory -Age 4–8 years: worse performance on tasks related to visual perception, language comprehension, attention and memory -Age 9–12 years: no difference in global IQ, performance on visual tasks, impulse control
Maternal Health Practices and Child Development Study (N=564)52 Pittsburgh, Pennsylvania 1982	Low-income, predominantly African-American	-Age 3 years: no differences in intelligence testing -Age 6 years: decreased verbal reasoning among offspring with exposure to one or more joints per day in first trimester -Age 10 years: decreased attention, more hyperactivity and impulsivity, worse academic performance when exposed in the first and third trimesters -Age 14 years: lower scores in reading, math and spelling especially with first trimester exposure
Generation R Study (N=9,778)53 Rotterdam, Netherlands 2001	Higher socioeconomic status, multi-ethnic	-Age 18 months: higher aggression scores in exposed girls, but not boys -Age 3 years: no differences in behavior -Ongoing follow-up planned into adulthood for children born April 2002–January 2006