Marijuana, also known as cannabis or ganja, is obtained from the flowers, leaves, and the seeds of the cannabis plant. Hashish is the name of the sticky resin obtained from the flowers of the female cannabis plant. Marijuana contains almost 60 cannabinoids, the psychoactive compounds, of which the main active chemical is the THC or the delta-9-tetrahydrocannabinol.
Cannabis has been used by the mankind since ancient times. However, a growing trend of using it for recreational and medicinal purposes was witnessed in the 20th century. Many countries of the world prohibit the use, possession, and sale of this drug. However, the supporters of medical marijuana claim that weed can have several health benefits, if used in proper dosage.
Effects of Cannabis on the Brain
More than 400 different chemicals are found in the cannabis plant, of which 60 chemicals come under the category of cannabinoids. THC is the main cannabinoid that is responsible for producing the typical effects that weed users’ experience.
- When marijuana is inhaled, the compound THC reaches the brain within a few seconds and activates its reward system. This is the reason why the users of marijuana experience euphoria and a sense of relief from stress or anxiety. The users often describe the effects of marijuana as somewhat relaxing and mellow.
- In the brain, the compound THC binds to the cannabinoid receptors of the nerve cells. These receptors are normally activated by the neurotransmitter anandamide. Anandamide is actually a type of cannabinoid, just like THC. So, THC basically mimics the actions of anandamide by binding to the cannabinoid receptors present in the brain.
- The cannabinoid receptors are mostly found in those regions of the brain, which control short-term memory, thought, coordination, sensation of pleasure, learning, and problem solving. A large of number of these receptors are present in the hippocampus, cerebellum, and basal ganglia. Located within the temporal lobe, the hippocampus is concerned with retaining short-term memory. So, a high level of THC can affect short-term memory or the ability to recollect recent events, by binding to the cannabinoid receptors present in the hippocampus.
- THC can also bind to the receptors found in the cerebellum and basal ganglia, which are responsible for maintaining coordination and unconscious muscle movements respectively. So, THC can affect coordination by acting on the cerebellum and basal ganglia.
- Dopamine is the neurotransmitter that is known as the feel-good brain chemical, mainly because it activates the brain's reward system. THC can stimulate the brain cells to release dopamine, and thus produce a pleasurable sensation.
- Apart from these, many people feel an increase in their appetite after smoking marijuana. This effect can also be attributed to the compound THC. THC is thought to increase appetite by interacting with the cannabinoid receptors present in the hypothalamus.
The cannabis plant has been in use for medicinal purposes for a long period of time. So far, medical cannabis has been legalized in several states of the United States, Canada, and five European countries, when it is recommended for pain relief, nausea, and for relieving certain symptoms associated with chronic illnesses
. Several studies have also been carried out to find out the positive effects of THC and other cannabis compounds, and many of which have noted that these compounds can actually have some positive health effects.
Though several studies have been conducted to find out the effects of continuous or long-term use of cannabis on the brain, their results are largely inconsistent. So, we have limited understanding about the long-term effects of marijuana on the brain
. Only future research in this area can give us a definite answer whether marijuana is addictive or whether it has any adverse effect on the brain. However, its regular use at an early age is largely believed to be associated with an increased risk of mental illnesses.