There are approximately 12 million users in the United States. THC is the abbreviation for tetrahydrocannabinol. This is the chemical in the plant, which causes the psychoactive effect desired by the abuser. Today's marijuana is not the same drug as it was 20 years ago. The informed illegal grower to push the plant into producing the highest grade, most potent product uses all special fertilizer, plant hormones and steroids, carbon dioxide, and advanced horticultural techniques.
Domestic marijuana is the most potent and highly prized cannabis product in the world.
In 1970, the average THC content of the marijuana plant was 1.5 percent. Today's grower has been able to push the THC content to 8 to 20 percent. Besides the well known psychoactive effects caused by THC contained in marijuana, there is accumulating evidence of marijuana's harmful biological effects. Marijuana contains known toxins and cancer inducing chemicals, which are stored in the fat cells for long periods of time. Scientific research relates marijuana use to long term impaired effects on the brain, the respiratory system, the immune system, and the reproductive process.