Let me present a fact based account on the pros and cons of marijuana.
THC (delta-9-tetrahydrocannabinol) is the mind-altering chemical in marijuana. In testimony to a US Congress subcommittee, Nora D. Volkow, MD, on June 24, 2014, stated that “scientific research has shown significant adverse effects (of marijuana) on health and well-being of people.” But this is only one side of the story.
The synthetic form of THC going under the trade name of Marinol was approved for medical use in May 1985 and was used to treat nausea and vomiting caused by chemotherapy. This product was approved by the US FDA to treat anorexia in patients with AIDS too (Eddy, 2010).
Marijuana has both short- and long-term effects on the brain. The THC in marijuana, when smoked or ingested in drink and food, is known to pass into the bloodstream quickly. The intoxication lasts for 30 minutes to one hour after ingestion.
The drug activates the brain, and there is a feeling of a high, change in mood, impaired body movement, impaired memory, and difficulty with thinking and problem-solving. Long-term effects can permanently impact the human brain.
Marijuana smoke irritates the lungs and impairs breathing. Heart rate is faster and stays up for three hours after use. In those susceptible to heart ailments, this can trigger heart attacks. The drug can impact the development of the brain of a fetus and should be avoided by pregnant women.
Marijuana use can lead to hallucinations, paranoia, schizophrenia, depression, and anxiety, and marijuana tends to addictive (Anthony, 1994; Lopez-Quintero, 2011).
According to the Indian Central Science and Industrial Research publication, Cannabis plants are used as a tonic, intoxicant, stomachic, anti-spasmodic, analgesic, narcotic, sedative, and anodyne in folk medicine. Seeds and leaves are used to treat cancerous ulcers and tumors.
A decoction of the root is said to help remedy hard tumors and knots in the joints. Other folk uses include treating delirium, depression, diarrhea, dysentery, dysmenorrhea, epilepsy, fever, gonorrhea, migraine, neuralgia, rheumatism toothache, uteral prolapse, etc.
Cannabinoids found in marijuana were studied for their antioxidant and neuroprotectant property. A US Department of Health and Human Services patent US 6630507 B1 was awarded to Aidan J. Hampson, Julius Axelrod, and Maurizio Grimaldi in October 2003. The abstract citation is reproduced below:
Cannabinoids have been found to have antioxidant properties, unrelated to NMDA (N-methyl-D-aspartate) receptor antagonism. This new-found property makes cannabinoids useful in the treatment and prophylaxis of wide variety of oxidation associated diseases, such as ischemic, age-related, inflammatory and autoimmune diseases. The cannabinoids are found to have application as neuroprotectants, for example in limiting neurological damage following ischemic insults, such as stroke and trauma, or in the treatment of neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease and HIV dementia. Nonpsychoactive cannabinoids, such as cannabidiol, are particularly advantageous to use because they avoid toxicity that is encountered with psychoactive cannabinoids at high doses useful in the method of the present invention…
Cannabis contains choline, eugenol, guaiacol, nicotine, and piperidine, all listed as toxins by the National Institute of Occupational Safety and Health (C.S.I.R., 1948-1976).
The association between marijuana use and adverse cardiac events like myocardial infarction, sudden cardiac death, cardiomyopathy, stroke, transient ischemic attack, and cannabis arteritis has been made (Thomas et al., 2014). The association between marijuana and polysubstance abusers and higher prospects of HIV infections was made in a study conducted in the US (Andrade et al., 2013).
The long-term effects of cannabis use on cognitive functions have also been studied and established (Crean et al., 2011). Lynsky (2000) has studied the effects of adolescent cannabis use on educational attainment and noted a negative correlation. Further, the relationship between marijuana initiation and dropping out of school has been established (Bray et al., 2000).
Researchers have consistently observed that cannabis use is associated with the onset of schizophrenia later in life. Some individuals are observed to be more vulnerable to schizophrenia when compared to others. Studies on animals have indicated that use during adolescence carries high risk (Casadio et al., 2011).
Exposure of the fetus to marijuana impacts the development of its brain.
A study conducted by Tashkin (2013) could not associate respiratory impairment with even prolonged smoking of marijuana. Probable association with higher levels of THC may still exist.
There does appear to be consensus on the psychological impact of marijuana, as with any drug that has psychoactive components and action. Components of marijuana are under investigation about its effectiveness as a treatment for autoimmune diseases and malignancy (Owen et al., 2014).
The association of marijuana with lung and upper-aerodigestive track cancers could not be established in a California-based case-control study (Hashibe et al., 2006). However, another case-control study, also conducted in California, has shown an association between marijuana use and nonseminoma and mixed tumors (Lacson et al., 2012).
To know about marijuana you can read the section on the plant here.