Cognitive effects in midlife of long-term cannabis use

Over the next decade, researchers will use neuroimaging technology to track brain development from late childhood to early adulthood. However, long-term marijuana may increase a person’s risk of substance use disorders, as well as problems with memory and concentration. In one 2016 study, researchers compared changes in the IQ scores of adolescent twins when one used marijuana, and the other did not. Some studies suggest that THC has potentially permanent neurotoxic effects that impair people’s verbal learning, memory, and focus. Both cannabinoids, such as THC, and these natural endocannabinoids, bind to the same receptors in the brain. When a person smokes marijuana, they may notice they struggle with staying focused or recalling important details.

Chronic effects

Older adults using cannabis should be aware that cannabis may affect them differently.22 Tell your physician if you experience unusual dizziness or lightheadedness, and be alert to your fall risk. Especially for newbies, starting with a low dose and gradually increasing it is best.20 Don’t use more until you know how the dose affects you. You need to understand how your body reacts to cannabis to minimize your risk of adverse effects. If this is an area of concern, it is best to discuss options with a healthcare provider until ongoing research gives us a clearer picture of these and other long-term effects. It is also worth noting that a subset of the study participants who used marijuana in adolescence had slightly better working memory scores than those who did not use marijuana.

Age-appropriate Use

Some people will use both alcohol and cannabis, often at the same time, which may both worsen the potential impact on memory. The localizations of cannabinoid receptors also are consistent with important roles in reward, reinforcement, and addiction. CB2 receptors are expressed in dopamine neurons of the midbrain ventral tegmental area (19), where effects on THC receptors may modulate addiction-related behaviors, such as drug reinforcement (19).

The Role of Dosage

Several studies have demonstrated the potential role of gene variation on the development of psychosis due to cannabis use (NIDA, 2019a). It has been found that risk of psychosis among the daily cannabis users carrying a specific variant of AK21 gene is seven times higher compared with those who use it infrequently or never used (Di alcohol-related deaths what to know Forti et al., 2012). Another study revealed an increased risk of psychosis among adults who carry a specific variant of the gene for catechol-O-methyltransferase (COMT) enzyme and used cannabis during adolescence. This enzyme can degrade different neurotransmitters for instance, dopamine and norepinephrine (Caspi et al., 2005).

Using marijuana can cause damage to brain cells that results in a number of concurrent symptoms throughout the body. Amphetamine abuse – Drugs like Adderall are not likely going to cause any major brain damage or loss of neurons if used properly. However, if you abuse amphetamines, it can have detrimental effects on cognitive functioning even years after use.

In parallel CB1 activation promotes the upregulation of mitogen-activated protein kinase (MAPK) which is involved in directing cellular responses to mitogens, heat shock, osmotic stress, and proinflammatory stimuli (e.g. cytokines). At the mitochondrial level, CB1 activation leads to inhibition of mitochondrial respiration and production of cAMP. CB1 receptors are also present at the level of lysosomes where they prompt a release of calcium from these internal storage units and increase the intracellular calcium levels. Using microelectrodes implanted into the brains of anaesthetized rats, the researchers found that the compound weakens the connections, or synapses, between neurons in the hippocampus, a structure that is crucial for memory formation.

To test their idea, researchers used genetically engineered mice with a mutation that mimics a genetic risk for psychiatric disorders in humans, along with normal mice as a comparison group. The mice carrying the mutation show changes to the brain with or without THC, specifically to the areas responsible for emotion, learning and memory. Research to date has suggested that acute and chronic use of cannabis leads to cognitive impairments (111,112).

Other work showed that abnormalities in hippocampal volume and shape may be seen in individuals who have cannabis dependence, and not necessarily in those who engage in regular cannabis use without exhibiting dependence (52). More research is needed to fully understand the long-term effects of marijuana on the brain, but there is enough evidence to suggest that chronic marijuana use can result in serious negative effects on brain development, IQ, cognitive function, and mental health issues. Inhalants – The poisons in inhalants can cause major problems in regards to brain functioning and can damage many brain cells. If you chronically sniff or huff things like paint and glue, you are risking your brain.

Addiction treatment can help people overcome marijuana addiction and improve their quality of life. Anesthesia – Many types of anesthetic drugs can cause significant brain impairment and even memory problems after use. Although anesthesiologists are highly trained professionals, the anesthesia exposure can wipe out some brain cells. Although there isn’t conclusive evidence in humans that anesthetic drugs kill brain cells, there is significant evidence in rats and mice. Currently there hasn’t been any direct research conducted in humans to find whether anesthesia causes neuronal death. Carbon Monoxide poisoning – Carbon monoxide poisoning basically deprives the brain of oxygen while poisoning them.

1. After prolonged use of synthetic marijuana, brain cell activity is likely to decline with a concurrent increase in negative physiological symptoms like the ones above.
2. As a result, motor functional recovery is increased which is beneficial for improving the outcome of aged patients as well as reducing their disabilities after chronic stroke (Bravo-Ferrer et al., 2017).
3. They have less negative and more positive symptoms compared with non-users, and they respond less well to antipsychotic treatment [6].
4. The researchers found that the rats they exposed to cannabinoids had a significantly better working memory in adulthood than the control rats.
5. Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.
6. It has been suggested from this research that, COX-2 inhibitors can prevent these cognitive deficits which may act as a potential target for future studies (Jouroukhin et al., 2019).

They studied levels of nerve growth factor (NGF) in a large group of schizophrenic patients who abused cannabis, showing that cannabis abusers had significantly higher serum NGF levels than nonabusers or controls. Since NGF is released after neuronal damage, they concluded that the increased serum NGF could be evidence of cannabis induced neurotoxicity. However, this study needs further replication and correlation to direct effects on brain tissue. Three biomedical literature databases, PubMed, Google Scholar, and ScienceDirect were searched up to July 2019.

This THC can be taken up from dried buds and leaves by smoking as well as it can be taken in other forms for instance edibles, waxes, oils, liquid incense, or vapor for both medical and recreational uses. For medical purpose, cannabis has been used to treat nausea and vomiting due to chemotherapy, neuropathic pain related to cancer and advanced neurological disorders (Singh et al., 2018). Therefore, in spite of being listed as a schedule 1 substance according to the Section 202 of the Controlled Substances Act of 1970 by Drug Enforcement Administration of USA, the use of cannabis has been legalized or decriminalized in different states of USA (Singh et al., 2018).

Sarafian et al. have previously shown that marijuana cigarettes promote the formation of ROS while lowering the intracellular levels of glutathione (Sarafian et al., 1999). In addition, other investigators found that THC, the main psychoactive component in the cannabis, acts as a potent promoter of OS and inflammation, thus appearing as a risk factor for the onset of ischemic stroke (Wolff et al., 2015b). In vitro studies using amyloid-beta-stimulate PC12 neurons CBD could inhibit the activity of inducible nitric oxide synthase, thus preventing the production of nitric oxide and reducing OS (Esposito et al., 2006). By contrast, in vivo studies to assess the protective effect of cannabis treatment against OS development and nigrostriatal cell injury induced by intrastriatal injection of rotenone did not produce any significant result (Omar, 2015). Unfortunately, there are contrasting results concerning the oxidative and antioxidative property of cannabinoids.

Summary of population-based analysis related to cannabis use, conducted between 2000 and 2015. List of case reports related to neurovascular complications after natural and synthetic cannabinoid use (according to year; 1964–2019). Smoking a 500 to 1,000 mg cannabis cigarette provides a THC dose of 0.2–4.4 mg where a pharmacologic effect of cannabis requires a dose of 2–22 mg. The THC level in the brain typically represents only ∼1% of the administered dose and usually corresponds to 2–44 μg. Read about a study that has uncovered the clearest picture to date of the CB1 receptor.

Studies examining structural alteration in the brains of cannabis users in chronological order. This review explores what is known about cannabis’s association with schizophrenia, cannabis’s effects on the brain, and whether the brain changes known to be present in schizophrenia could be caused by cannabis after the high the dea and thus lead to a psychosis. To examine the effect of cannabinoids on blood circulation as well as reactive vasodilation or vasoconstriction, particularly focusing on the cerebral vascular bed, several studies on rat, mouse, rabbit, cat, and pig models were performed (Richter et al., 2018).

More research is also needed to determine whether each form of use — including smoking, vaping, and ingesting edibles — has a different effect on your brain’s overall health. But the approach has risks, says Dr. Ginger Nicol, a psychiatrist at after-work drinking Washington University whose husband was in the study and took psilocybin twice. A patient with addiction, for example, might be able to reframe their relationship with substances in the days and weeks following a dose of psilocybin, he says.

It is likely that cannabis potentiates a neurochemical deficit in the dopaminergic pathway that causes the above effects (see below), but whether it is causing structural damage to the already compromised brain structure of someone with chronic schizophrenia is unknown. Mounting evidence points to cognitive impairment after chronic, heavy cannabis use (133–135), enduring beyond the acute effects, although there is also a large body of evidence with negative findings in cannabis users (136–138). Consistency in experimental design remains a challenging aspect of studying the long-term effects of chronic cannabis use on cognition (141). As recreational marijuana use becomes legalized throughout the US, many people now wonder how marijuana affects the brain and whether or not it kills brain cells. Just as years of heavy alcohol, meth, and heroin use can cause some irreversible brain damage, prolonged marijuana abuse can affect the ability of brain cells to convey messages (also known as brain activity).