I don't know anything about the brain damage studies, but isn't there an increased risk of schizophrenia if an already predisposed individual uses marijuana during their late teens?

Really though, the health argument over marijuana is a smokescreen. There are many, many pharmaceutical drugs that have far more serious known side-effects than what marijuana might have. The real aversion is they don't want to legalize something that people can high off of.

However, if you're dealing with strains that have a really low THC level it wouldn't be prone to that kind of abuse, because it wouldn't give the desire effect. Equating the two would be like lumping together a 40% alcohol Tequila with a 0.5% alcohol cooler.

If they are willing to distinguish between poppies, why lump together all the marijuana strains?