Thursday, June 16, 2022

How Does Thc Affect The Brain

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Cannabinoids And The Neocortex

How does marijuana affect your brain?

Like other intoxicant drugs cannabis causes profound changes in a variety of higher brain functions. The literature on the acute effects of the drug in human subjects is large, and can only be summarized here . The distribution of CB1 receptors in the neocortex has been described in detail . As in the hippocampus, the majority of cortical interneurons expressing high levels of CB1 receptor are GABAergic cells, which also express cholecystokinin . CB1positive terminals are concentrated in layers IIIII and layers VVI, with few in layers I or IV. Despite the obvious importance of the abundant CB1 receptors in the neocortex there have so far been few electrophysiological studies of their effects on neural activity.

have suggested that anandamide may play a role in the control of the sleepwaking cycle.

The Effects Of Marijuana On Your Memory

As you get older, certain aspects of memory normally decline, but that does not mean you are powerless to protect your brain as you age. In fact, there is a lot you can do. In addition to getting regular exercise and eating a Mediterranean style diet, you can also consider what is known and not known about marijuana.

Is weed bad for your brain?

Cannabis contains varying amounts of the potentially therapeutic compound cannabidiol , which may help quell anxiety. However, there’s no question that marijuana can produce short-term problems with thinking, working memory, executive function, and psychomotor function . This is because marijuana’s main psychoactive chemical, THC, causes its effect by attaching to receptors in brain regions that are vital for memory formation, including the hippocampus, amygdala, and cerebral cortex. The extent to which long-term use of marijuana produces persistent cognitive problems is not known.

The laws regarding differ from state to state. Some outlaw it altogether, while others allow it for medical purposesto help relieve pain and nausea, for example. And in a growing number of states, marijuana is legal for recreational use. But it remains illegal at the federal level. For that reason, it has been difficult for researchers in the United States to obtain federal research funding to study marijuana, limiting the amount of high-quality evidence available.

What Do We Know About The Long

Cannabis is the most widely used illicit drug in the U.S., so it shouldnt be too much of a surprise that teens use it though the numbers are still quite high. A 2020 survey found that:

  • 11.4% of 8th graders had used cannabis in the past year, and 6.5% had used it in the past month.

  • 28% of 10th graders had used cannabis in the past year, and 16.6% had used it in the past month.

  • 35.2% of 12th graders had used cannabis in the past year, and 21.1% had used it in the past month.

According to the same survey, these rates have been fairly steady over the past 15 years. At the same time, the survey found that the percentage of adolescents who view cannabis use as risky has declined.

A number of studies have looked at how cannabis use during adolescence might interfere with brain development, IQ, and cognitive abilities. Generally, these studies have found that cannabis use can affect how the brain matures. But there are some caveats.

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How Thc Works In The Brain

The plant known colloquially as weed, pot, dope, and ganja has been given the scientific name cannabis sativa. It is a close relative of the similarly named cannabis, which is the name given to hemp grown for industrial uses. The major difference between the two is that cannabis sativa contains the compound tetrahydrocannabinol in large amounts as well as cannabidiol . However, hemp only contains trace amounts of THC and is rich in CBD.

Those familiar with cannabis know that it can make people high thanks to the THC compound in the plant. To understand fully how THC works in the brain, lets go back to biology class for a quick neurobiology lesson.

Effects Of Cannabinoids On Hypothalamic Control Of Appetite


Many subjective reports suggest that cannabis intoxication is associated with an increased appetite, particularly for sweet foods, even in subjects who were previously satiated. This effect can be confirmed under laboratory conditions , although results from studies in human subjects have tended to be variable, perhaps because the increased appetite is focused on certain types of food. Nevertheless, controlled clinical trials showed that THC had significant beneficial effects in counteracting the loss of appetite and reduction in body weight in patients suffering from the AIDSrelated wasting syndrome , and this is one of the medical indications for which the drug has official approval in the USA.

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The Effects Of Thc On The Body

THC stands for Tetrahydrocannabinol and is a cannabinoid commonly found in cannabis. It is psychoactive, which means that it is able to influence its user psychologically. You will normally find THC in the resin gland of a cannabis plant.

According to the NIDA , THC is broadly the same as the cannabinoids that each of us naturally produces. The cannabinoid receptors are able to communicate with certain areas of the brain which are in charge of producing pleasure, thinking and retaining information, whilst also having an effect on perceiving time and body coordination.

THC binds itself to these receptors in the brain and this is how it offers its effect.

Effect Of Marijuana Use On Iq

The effect Marijuana has on the brain is influenced by the amount a person has smoked and the users age. Individuals under 25, whose brains are still developing, are most susceptible to the effects of Marijuana on the brain. A study of Marijuanas effect on IQ revealed individuals who began using Marijuana at a young age lost 6 to 8 points from their IQ by middle age. Moreover, those who smoked Marijuana throughout their adolescence, then stopped, did not regain their IQ points. Conversely, individuals who began using Marijuana in their adulthood did not experience any IQ loss.

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Cannabis Products Are Everywhere These Days

Cannabis products are everywhere these days. As a growing number of states loosen their medical and recreational cannabis laws, millions of Americans are using the cannabis sativaplant, typically known as , to relax or treat pain, anxiety, insomnia, and other conditions. Yet more data is needed on its impact. The nation has warmed toward the use of cannabis, but policy continues to outpace the science, says neuroscientist Staci Gruber, EdM 95, PhD, whos working to change that.

Gruber, a Harvard Medical School associate professor of psychiatry, directs both the Cognitive and Clinical Neuroimaging Core and the program at McLean Hospital. She and her team are using cognitive and clinical measures, as well as neuroimaging techniques like functional MRI, to help elucidate how cannabis affects the human brain. They have discovered, for example, that individuals who start heavy recreational marijuana use before age 16when the brain is still developingmay perform more poorly on cognitive or behavioral tasks involving the frontal cortex, such as memory, attention, and judgment, than those who dont use cannabis or who started using it later in life. A recent paper that Gruber co-authored underscored these findings using results from a simulated driving test. Neuroimaging has also revealed changes in white matter, the neural fibers critical for efficient communication among brain regions, in early-onset cannabis users.

Cannabis And Psychiatric Illness

How Marijuana Affects the Brain: THC & CBD

A temporary form of druginduced psychosis can occur in some cannabis users. In some of the psychiatric literature this is referred to as cannabis psychosis . Research psychiatrists, particularly in Britain , have studied this condition carefully. It nearly always results from taking large doses of the drug, often in food or drink, and the condition may persist for some time, perhaps as the accumulated body load of THC is washed out. The acute toxic psychosis that is sometimes caused by cannabis can be sufficiently serious to lead to the subject being admitted to hospital, and the initial diagnosis can be confused with schizophrenia, since the patients may display some of the characteristic symptoms of schizophrenic illness. These include delusions of control , grandiose identity, persecution, thought insertion, auditory hallucinations , changed perception and blunting of the emotions. Not all symptoms will be seen in every patient, but there is a considerable similarity to paranoid schizophrenia. This has led some to propose a cannabinoid hypothesis of schizophrenia, suggesting that the symptoms of schizophrenic illness might be caused by an abnormal overactivity of endogenous cannabinoid mechanisms in the brain .

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Cannabis And The Endocannabinoid System

The endocannabinoid system is phylogenetically old, having been identified in the most primitive animals with a neuronal network. In animals, N-arachidonoylethanolamine and 2-arachidonoyl glycerol are the major endocannabinoids. Many of their effects and those of phytocannabinoids are mediated by CB1 and CB2 receptors, which primarily couple to G proteins of the Gi and G0 classes, although some cannabinoids engage other receptors . CB1 receptors, which mediate many of the psychoactive effects of cannabinoids, are found in high densities in several brain regions and the eye, and in lower densities throughout the body . Among the most abundant G protein-coupled receptors in the brain , they are localized primarily to neurons but also are expressed in glia . CB2 receptors are found in immune cells and in some neurons. The endocannabinoid system comprises these receptors, the endocannabinoids anandamide and 2-AG, and the enzymes that regulate their production and degradation .

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 , where effects on THC receptors may modulate addiction-related behaviors, such as drug reinforcement . CB1 and mu receptors are co-localized in striatal output projection neurons of the nucleus accumbens and dorsal striatum, which modulate reward and habit formation, respectively .

Inhibition Of Neurotransmitter Release

The presynaptic localization of CB1 receptors suggests a role for cannabinoids in modulating the release of neurotransmitters from axon terminals, and this has been confirmed by a substantial body of experimental data. Early reports showed that THC inhibited acetylcholine release from electrically stimulated guinea pig ileum. Similar inhibitory effects of THC and other cannabinoids on the release of a variety of neurotransmitters from CNS neurons have been observed in many subsequent studies . The neurotransmitters involved include lglutamate, GABA, noradrenaline, dopamine, 5HT and acetylcholine. The brain regions most often studied in vitro, usually in tissue slice preparations, have been cerebellum, hippocampus or neocortex. Neurotransmitter release has been studied directly in superfused preparations, and indirectly by measuring postsynaptic currents. Although most of these studies involved rat or mouse brain, a few studies have shown similar results using human brain tissue . Because THC is only poorly water soluble, the more soluble synthetic CB1 receptor agonists WIN552123, HU210 or CP552940 were used in these in vitro studies. The specificity of the cannabinoid effects were confirmed by demonstrating that the inhibitory effects of the agonists were completely blocked by the CB1selective antagonist rimonabant.

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Acute Effects Of Marijuana On Psychomotor Skills

Since cannabinoid receptors are abundant in the basal ganglia and cerebellum , and these parts are associated with psychomotor skills, its no coincidence that the use of marijuana has an immediate effect on your psychomotor skills.

Most studies that looked at the effects of marijuana on psychomotor skills found that especially THC has the potential to impair psychomotor function .

Most of the studies that looked at the acute effects of marijuana on psychomotor skills found that:

  • The more THC is in your system, the worse the impairment, and
  • The less frequent you use marijuana, the worse the impairment .

In a meta-analysis of 150 experimental studies that looked at the effects of marijuana on physical activity, researchers found that smoking marijuana acutely impaired the following physical performance areas :

  • Tracking

How does this information apply to your marijuana use?

Its clear that marijuana can severely influence your psychomotor skills and reaction time.

NEVER drive while under the influence of marijuana. Especially the first few hours after smoking/vaping it your psychomotor skills, attention, and reaction time can be severely impaired.

Besides driving, just avoid any type of physical activity in which its possible to hurt yourself or others and which needs a high level of attention, reaction time and/or a high degree of psychomotor skills.

Physical Changes In The Brain Caused By Long


The physical changes in the brain refer to brain volume and the increase/decrease of specific types of brain substances like gray matter and neurons.

Heavy and chronic use of any psychoactive substance has the potential to change your brain volume and brain chemistry in a significant way.

But is there any evidence for marijuana?

Currently, theres one brain part where researchers found that heavy and frequent marijuana use can lead to a significant reduction in the volume of gray matter:

  • The hippocampus.

This finding is based on the largest systematic review study, which scrutinized the results of 14 studies that looked into structural brain alterations caused by marijuana .

The hippocampus is mainly associated with short-term memory, long-term memory, and spatial navigation. This means that heavy and frequent marijuana use can negatively influence all of these brain functions.

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Probable Mechanism Associated With Cannabis

It is evident from various studies that, consumption of cannabinoids through inhalation and combustion, is associated with the occurrence of cerebral infarcts . Natural cannabis and synthetic cannabinoids may act as possible trigger for reversible intracranial vasoconstriction which along with severely reduced cerebral blood flow could be a major prodromal factor to neuronal death by ischemia .

Figure 4 Schematic illustration of the Activation of the cellular antioxidative response system under normal and stress condition. Under normal conditions, the response to injury is adaptive, designed to restore homoeostasis and to protect the cell from further injury. In response to excessive oxidative stress stimuli, NADPH oxidase is activated, producing an excess of O2â which in the presence of nitric oxide results in formation of peroxinitrite . Furthermore, the excess of H2O2 leads to the formation of hydroxyl radicals . The unchecked OS leads then to mitochondrial depolarization, lipid peroxidation, DNA fragmentation and inflammation which at the cerebrovascular level can cause BBB damage and ultimately facilitate the onset of CNS diseases.

Effects Of Marijuana On The Nervous System

THC acts on cannabinoid receptors which are found on neurons in many places in the brain. These brain areas are involved in memory , concentration, perception and movement . When THCactivates cannabinoid receptors, it interfers with the normal functioningof these brain areas. In low to medium doses, marijuana causes:

  • relaxation
  • sleepiness
  • disruption in attention
  • an altered sense of time and space…a goodreason not to drive or operate machinery while under theinfluence.

In high doses, marijuana can cause:

  • hallucinations
  • impaired memory
  • disorientation.

Scientists have known for a long time that THC interacted withcannabinoid receptors in the brain, but did not know why the brain wouldhave such receptors. They thought that the brain must make some kind ofsubstance that naturally acted on these receptors. In 1992, they foundthe answer…anandamide. Anandamide is the brain’s own THC . Still, scientists are not surewhat the function of anandamide is in the normal brain.

The effects of marijuana start as soon as 1-10 minutes after it istaken and can last 3 to 4 hours or even longer. Experiments have shownthat THC can affect two neurotransmitters: norepinephrine and dopamine. Serotonin and GABA levels may also be altered.

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Exogenous Cannabinoids And Their Receptors

The principal active component in the complex mixture of cannabinoids present in extracts of the plant Cannabis sativa is 9tetrahydrocannabinol . THC is a sticky resin that is not soluble in water. Smoking remains the most efficient means of delivering the drug and experienced users can titrate the dose by adjusting the frequency and depth of inhalation . THC or cannabis extracts can also be taken orally in fatcontaining foods or dissolved in a suitable pharmaceutical oil, but absorption is delayed and variable . A series of manmade synthetic cannabinoids, some of which are more potent and more water soluble than THC, is also available . All of these compounds act as agonists at the CB1 cannabinoid receptor , which is the only one known to be expressed in the brain. A second cannabinoid receptor, CB2, is expressed only in peripheral tissues, principally in the immune system . THC and the synthetic cannabinoids also act to some extent as agonists at the CB2 receptor. Both cannabinoid receptors are members of the Gprotein coupled class, and their activation is linked to inhibition of adenylate cyclase activity . A series of synthetic drugs is also now available that act as specific antagonists at CB1 or CB2 receptors . One of these compounds, rimonabant, which acts selectively to block CB1 receptors , has been widely used in studies of the actions of cannabinoids in the CNS .

The Short Term Effects Of Marijuana Vary

How Marijuana Affects Your Developing Brain

Although the exact same biological processes occur in everyone who smokes or consumes cannabis, the way those processes make people feel varies wildly.

Some people are incredibly sensitive to THC while others are less sensitive, Gruber says. Some get very paranoid others have no problem. Some people say oh my god, I got so hungry and ate everything in the house while others dont get hungry at all. If someone hands you a bowl or a vape cartridge of Granddaddy Purple, you will very likely have a different experience than they do, even though youre smoking the same stuff.

There are many potential reasons for this. So much of it depends on previous use history, whether you have some familiarity with THC and other substances, Gruber says. It also depends on your individual body chemistry and metabolism, as well as the product itself, whether its a cultivar that has high amounts of other cannabinoids that mitigate the effects of THC.

Another factor is how activated a persons endocannabinoid system is before they use cannabis. Lets say 70 percent of your receptors are activated and only 20 percent of that persons receptors are activated right before they use marijuana, Piomelli says. Because of this difference, you might become panicky after smoking while the other person feels more relaxed. This also explains why the same person can feel different effects on different occasions even if they consume the same product both times.

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