Cannabis most harmful to under-18′s

A remarkable long-term study of 1,000 individuals in New Zealand has found that those who regularly used cannabis in their youth lost up to eight IQ points as adults compared to before they began to use cannabis.  Long-term use has already been associated with negative effects on memory and concentration.  Some users become tired and demotivated resulting in underachievement in education and in the workplace.  The drug has also been linked with the onset of psychosis in genetically predisposed individuals.  Add to these consequences a measurable loss of IQ and it is difficult to see how cannabis can be considered harmless, particularly for those who start young and use frequently.