Intelligence quotient, increased

In a third study the Robert Wood Johnson database of published literature on prenatal cocaine exposure and child outcome was examined (274). Only 8 of 101 studies focused on school-age children. Intelligence quotient (IQ), receptive language, and expressive language were measured. This meta-analysis showed an average difference of 3.12 IQ points between cocaine-exposed and control groups. When the IQ distribution is shifted downwards by this amount, there is a 1.6-fold increase in the number of children with IQs under 70. The authors noted that the calculated decrement in IQ in exposed children is subtle and does not include the possible effect of the drug on domains of function such as language abilities. 

Nervous System Arsenic and manganese exposure is associated with neurodevelopment problems in children. Study reveals that a 50% increase of urine arsenic concentration and hair manganese levels may decrease the intelligence quotient (IQ) by 0.4 in children aged 5-15 years and by 0.7 in children aged 6-13years, respectively [48 ]. 

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