Marijuana is the most commonly abused psychoactive substance in the whole world. The United States is no exception. Throughout the years, there have been investigations on the negative and positive effects of marijuana on the human body and the brain. According to these findings, the possession, use, or sale of cannabis preparations containing psychoactive cannabinoids became illegal in most parts of the world in the early 20th century. Nevertheless, since then, the drug has been used for recreational, religious or spiritual, and medicinal purposes. It is estimated that 4% of world population, or 162 million people, use marijuana annually. Approximately 0.6% of world population, or 22.5 million people, use marijuana on a daily basis.
Marijuana, also known as cannabis, refers to a number of preparations of the Cannabis sativa plant, intended to use as a psychoactive drug. Marijuana consists of the flowers and subtending leaves and stalks of mature pistillate of female plants. This drug is also known by its numerous street names such as pot, weed, grass, ganja and skunk. The main active chemical in marijuana is delta-9-tetrahydrocannabinol or THC. As a psychoactive drug, marijuana can be consumed in many various ways, most of which involve inhaling smoke from pipes, bongs, paper-wrapped joints or tobacco-leaf-wrapped blunts. When a consumer smokes marijuana, THC rapidly passes from the lungs into the bloodstream, which carries the chemical to the brain and other organs throughout the body.
The effects of marijuana on the brain
THC affects certain regions in the brain, called cannabinoid receptors, resulting in a series of cellular reactions that eventually lead to the "high" that users experience when they smoke marijuana. Certain regions of the brain have many cannabinoid receptors while the others have just a few of them or even none. The highest density of cannabinoids is found in the brain areas responsible for pleasure, memory, thinking, concentration, sensory and time perception and coordinated movement. This is why most of the marijuana consumers experience distorted perceptions, impaired coordination, difficulty with thinking and problem solving and problems with learning and memory. In chronic users, marijuana has unfavorable effects on learning and memory that can last for a couple of days after the consumption. This means that someone who smokes marijuana every day may be functioning at a suboptimal intellectual level all of the time.
Chronic use of marijuana is also associated with increased rates of anxiety, depression, and schizophrenia. However, it is yet unclear whether marijuana causes mental problems, aggravates them, or reflects an attempt to self-medicate symptoms already in existence.