Marijuana is a mood altering molecule derived from a plant. It has been popular as an underground treatment that reduces anxiety and creates distortions of sensory input (particularly visual). It increases appetite, and alters pain perception. In the past regulation consisted of an outright ban on growing and usage. During the past several years many states have legalized it's use for medicinal purposes by requiring a physician's signature.
Marijuana is the most commonly used illegal substance in the world. Previous studies have suggested that frequent marijuana users, especially those who begin at a young age, are at a higher risk for cognitive dysfunction and psychiatric illness, including depression, bipolar disorder and schizophrenia.
Early marijuana use associated with abnormal brain function, study reveals