6 Scientifically Proven Long-Term Effects of Marijuana on the Brain & Body

By Carolina Martel

Posted 3 months agoHEALTH

Long-Term Effects of Marijuana on the Brain & Body

For fun, for relaxation, or whatever the reason, people use marijuana in a form of smoke, by adding it to tea, cookies, brownies and in many other ways.

The cultivation of marihuana of different types: Cannabis Indica and Cannabis sativa began some six thousand years ago. Nowadays it is a highly common drug used after alcohol in the United States of America. At present, it is a legal drug for recreational use in 10 states and for a medical use in 33 states of the USA for its wide-ranging health benefits.

Different parts of this plant can be used including stem, dried leaves, flowers, and even seeds to obtain the compressed form of marijuana. THC enriched resins are now also available in the market which is becoming a popular way of marijuana consumption. You can check out the buying weed online reviews to learn more about it.

Regardless of its usefulness for various medical purposes, its prolonged or heavy usage is detrimental to human health. It can affect the body and brain in numerous different ways and can also lead to unhealthy outcomes.

Here are the six scientifically proven long-term effects that marijuana poses to the body and brain:

Impaired Memory

Marijuana affects the brain’s region called the hippocampus which is responsible for regulation of short-term memory. Temporarily, consumption of cannabis hinders the brain to learn and make new memories.

The Molecular Psychiatry journal published a research related to false memories development because of consuming cannabis in large amounts.

Moreover, teens who smoked marijuana are prone to develop problems related to memory as adults according to another research. In teenagers, the hippocampus adapted an abnormal shape due to smoking marijuana daily for three years in their early adulthood. These were the findings of a study that the Hippocampus journal published. Those people with abnormally shaped hippocampus showed a poorer performance than non-marijuana users when a long-term memory test was taken.

In an animal-based research, issues related to learning and memory has been seen after THC’s exposure. THC or tetrahydrocannabinol is actually the most active element of marijuana responsible for the high it gives. It gets attached to the brain’s cannabinoid receptors whenever a person smokes marijuana; thus, causes altered functioning of the brain.

In another animal-based study, repeated exposure to marijuana made developing new memories difficult for the young rats in their later life. Adding to it, those rats were less social and their anxiety levels were also higher.

Problems with Respiration and Lungs

Long-term effects of marijuana may include problems in respiration. According to the findings of some experts, consuming marijuana regularly can contribute to the production of phlegm as well as a cough daily. Moreover, it can put the user at a higher risk of developing a lung infection. In addition, it can also reason illnesses of the chest more often.

At the University of California, a study concluded that marijuana is less harmful to the lungs in comparison to tobacco. Nonetheless, the same study suggested an elevated risk of damaged lungs as a result of higher marijuana consumption. However, there were many limitations in this study including a smaller number of users of marijuana in higher amounts..

Issues with the Reproductive System

Irrespective of gender, marijuana can negatively affect the reproductive system. It can increase infertility in men thus increasing the chances to 15 percent for couples to fail to conceive. Nonetheless, the related research is limited and hence less reliable.

In an animal-based research, low levels of testosterone have been seen in males after exposure to marijuana. Additionally, some scientists suggested a negative impact of THC on testosterone’s production.

Also, THC can be a contributor to infertility in men since it reduces the motility of sperm (Fronczak, Kim, & Barqawi, 2012).

As per some other animal-based studies, low levels of sex hormones were observed in females after their exposure to marijuana. Female sex hormones are inclusive of estrogen and progesterone low levels of which can disturb their ovulation cycle.

More importantly, THC can harm the growth and development of fetus if the mother is consuming marijuana in heavy doses during pregnancy.

As a whole, this field requires more research for getting accurate and generalizable results.

Numerous studies show an association between elevated risk of testicular cancer in males and marijuana consumption. Testicular cancer is the most common type of cancer among men below 45 years of age.

A 2012’s study revealed that male marijuana smokers were prone to have testicular cancer two times more than non-smokers. A peer-reviewed journal BMC published a study in 2015 that revealed an association between prolonged marijuana consumption and a higher probability of testicular cancer.

There have also been found neurological issues in the children born to the females who consumed marijuana while being pregnant.

Some research suggests the following effects of prenatal exposure of marijuana:

  • Elevated tremulousness
  • Problems in sustaining memory and attention
  • Alteration in responsiveness to visual stimuli

Mental Disorders and Disruptions

According to some studies, carrying particular genes may put you at higher risk of having schizophrenia if you consume marijuana. Schizophrenia is actually a terrifying mental disorder that affects the thinking, feelings, and behavior of a person.

Regular or heavy consumption of marijuana can cause depression and anxiety. Conversely, many people also use marijuana to ward off depression and anxiety. So, heavy dosage of marijuana may worsen the condition even more.

Regardless of the mixed results, some findings reveal that adolescents who regularly use marijuana develop higher anxiety levels in later life (Degenhardt et al., 2013). Additionally, frequent or heavy marijuana consumption in teens is linked with specific personality disorders, suicidal ideation, as well as interpersonal violence. Initiating its use at an early age makes you more prone to develop all such cognitive disorders in adulthood.

Smoking marijuana can lead to the development of another mental psychiatry disorder named psychosis rendering to some findings. In this type of disorder, a person starts to perceive and think abnormally. Its main symptoms are inclusive of hallucinations and delusions. More importantly, you can increase the risk of being psychotic by increasing the amount of marijuana. Due to carrying a certain gene, regular marijuana consumers are 7 times more prone to develop psychosis than non- consumers (NIDA, 2016; Caspi et al. 2005).

Problems with The Digestive Tract

Marijuana consumption causes burning or stinging in your oral cavity and throat after inhalation.

Also, it can cause problems with the digestive tract when consumed orally. Such as: consuming THC orally can cause vomiting and nausea. In addition, it may be damaging to the liver too.

On the contrary, medical treatment for an upset stomach or nausea also includes marijuana to relieve the symptoms.

The Munchies can also happen due to marijuana consumption which refers to the sudden urge to eat food. For this reason, marijuana is useful for the medicinal purpose during chemotherapy. However, this aspect can be disadvantageous for overweight and/or obese people.

According to two new case studies, consuming marijuana regularly can cause abdominal pain.

Problems with The Cardiac System

Rendering to the Centers for Disease Control and Prevention (CDC), cardiovascular disease is a major cause of death in America. The number of people who experience a heart attack every year is approximately 735,000.

Consumption of marijuana immediately causes the heart to beat at a faster rate. It can actually increase the heartbeat by 20 to 50 beats per minute. Furthermore, it also lowers the blood pressure.

Both these conditions four times increase heart attack’s risk in marijuana users than the in general when not consuming it.

Heart patients who consume marijuana in any form easily and rapidly develop chest pain according to the findings of experts.

In the survivors of heart-attack, there may be a long-term rate of death due to marijuana consumption as observed by the Harvard Medical School’s doctors.

Some experts also suggest avoiding using cannabidiol (CBD) to the people who are receiving cardiovascular treatment. Though CBD is a non-toxic component of marijuana, it can interfere with the blood thinners being used as cardiovascular medication.

Due to limited evidence, drawing any conclusion will be of no use. Therefore, there is a need to perform more research on marijuana consumption and its effects on the heart.

Bear in mind that excess of everything is bad so is the case with marijuana. Avoiding any kind of drug is highly advisable for ensuring a healthy life unless medical reasons.

Apart from the long-term effects of marijuana on the body, there is no evidence of death due to its overdosing so far. Nonetheless, you may experience severe side effects when consuming marijuana frequently or in larger amounts as stated earlier.

On top of that, a higher dosage of marijuana can increase the risk of accidents and injuries too. It can make the user dull and less interested in life which is a negative aspect in particular for teenagers. This is because they will perform poorly in academics and in turn, will get disappointed in life. It can also make them anti-social and will make them lifeless.




Caspi A, Moffitt TE, Cannon M, et al. Moderation of the effect of adolescent-onset cannabis use on adult psychosis by a functional polymorphism in the catechol-O-methyltransferase gene: longitudinal evidence of a gene X environment interaction. Biol Psychiatry. 2005;57:1117–27.[PubMed]

Copeland J, Rooke S, Swift W.  Changes in cannabis use among young people: Impact on mental health.  Curr Opin Psychiatry 2013;26:325-329. View abstract

Degenhardt L, Coffey C, Romaniuk H, Swift W, Carlin JB, Hall WD, Patton GC. The Persistence Of The Association Between Adolescent Cannabis Use And Common Mental Disorders Into Young Adulthood. Addiction. 2013 Jan;108(1):124-33. View abstract

Eisenberg, M. L. (2015). Invited. Commentary: The Association Between Marijuana Use And Male Reproductive Health. American Journal of Epidemiology, 182(6), 482-484.

Fronczak, C. M., Kim, E. D., & Barqawi, A. B. (2012). The Insults Of Illicit Drug Use On Male Fertility. Journal of Andrology, 33(4), 515-528.

“How Does Marijuana Produce Its Effects?”, NIDA, Mar 2016

O’Shea, M., Singh, M. E., McGregor, I. S., & Mallet, P. E. (2004). Chronic Cannabinoid Exposure Produces Lasting Memory Impairment And Increased Anxiety In Adolescent But Not Adult Rats. Journal of Psychopharmacology, 18(4), 502-508.

Pletcher, M. J., Vittinghoff, E., Kalhan, R., Richman, J., Safford, M., Sidney, S., … & Kertesz, S. (2012). Association Between Marijuana Exposure And Pulmonary Function Over 20 Years. Jama, 307(2), 173-181.

Smith, C. G., & Asch, R. H. (1984). Acute, Short-Term, And Chronic Effects Of Marijuana On The Female Primate Reproductive Function. NIDA Res Monogr, 44, 82-96.

 “What Are Marijuana’s Effects On General Physical Health?” , NIDA, Mar 2016


About the author Carolina Martel

Currently a student of English Literature, in her final years, Carolina Martel is passionate about writing her thoughts in words. She takes up writing projects in her leisure time to accompany her studies. Generally, she understands the essence of writing on every topic but especially those that relate to her field. She regularly writes at Shadedco.com.