Final answer:
The primary active ingredient in marijuana is delta-9 tetrahydrocannabinol (THC), which affects the brain to change mood and consciousness and is used in some FDA-approved medications.
Step-by-step explanation:
The primary active ingredient in marijuana is delta-9 tetrahydrocannabinol (THC). THC is one of many cannabinoids found in the marijuana plant which can alter brain function, affecting mood and consciousness. This compound is also involved in medical treatments and is an active ingredient in FDA-approved drugs that help mitigate nausea from chemotherapy and stimulate appetite in AIDS patients. Other cannabinoids like CBD are used in medications to treat severe forms of epilepsy in children.
Marijuana, being a psychoactive drug, has both recreational and medical uses. Recreationally, it is consumed for the 'high' it produces, which is primarily due to THC. Medically, the cannabinoids in marijuana, particularly THC and CBD, are of interest for their potential therapeutic effects on various health conditions, although the raw plant has not been FDA approved as a medicine. Ongoing research continues to investigate the broader medicinal properties of marijuana and its compounds.