The only "brain abnormalities" are found in the marijuana-less minds of the media. The U.S. media does not understand basic science reporting. The newspapers and television stations have sold their souls to the alcohol companies, and the alcohol companies are scared to death that Americans will wake up to the fact that weed is better for you than booze. They stand to lose billion$ and will lose billion$ when the country wakes up from its infatuation with fungi feces.
Articles that portray cannabis in an objective and scientific light may be found at NORML.
Weed costs next to nothing to produce, is non-toxic and non-addictive, is self-renewable, removes carbon from the air, produces many useful products besides marijuana, and has a pharmaceutical history spanning thousands of years, which is why we know for a fact that weed is safer than aspirin.
Alcohol is the toxic waste product of microorganisms feeding upon death and
decay, the bringer of madness and ill health. Weed is better than alcohol by any measure one could imagine. The living plant harnesses energy from the Sun to produce a substance that makes humans feel high. What weed does not do includes the whole list of negative attributes that belong to alcohol. It does not cause addiction, it does not cause insanity, it does not make the non-violent violent, and it does not harm its user.
There was never, at any time, a rational motive for making marijuana illegal. A return to sanity would be marked first of all by the legalization of marijuana for all purposes. However, human society is known for many irrational acts, such as war, crime, self-harm and collective self-harm, including pollution of the environment. The laws against marijuana seem almost insignificant by comparison to the many other signs of craziness. What is needed is a saner and more rational world that learns to love understanding and wisdom and reject lies and corruption.