The President of the International Narcotics Control Board (INCB), Raymond Yans, has voiced grave concern about the outcome of recent referenda in the United States of America that would allow the non-medical use of cannabis by adults in the states of Colorado and Washington, and in some cities in the states of Michigan and Vermont. Mr. Yans stated that “these developments are in violation of the international drug control treaties, and pose a great threat to public health and the well-being of society far beyond those states”.
Heavy marijuana use is associated with cognitive decline in about 5% of teens, according to a new study, which suggests that the heaviest users could lose 8 IQ points, according to a report, published in the Proceedings of the National Academy of Sciences. If the link is real, the effects on cognition could be dramatic. But intelligence and cognition is affected by a plethora of other factors, including genetic, social and environmental influences that may supersede any influence from drug use.