Teenagers who Smoke Cannabis Damage Their Brains for LIFE and May be More Likely to Develop Schizophrenia

Yet another study linking pot to brain-damage and schizophrenia in teens

By Ellie Zolfagharifard, Mail Online

Teenagers who regularly smoke cannabis suffer long lasting brain damage and are in much greater danger of developing schizophrenia. 

American researchers say the drug is particularly dangerous for a group of people who have a genetic susceptibility to the mental health disorder - and it could be the trigger for it. 

Asaf Keller, of the University of Maryland School of Medicine, said the results highlight the dangers of teenagers smoking cannabis during their formative years. 

The study found that even short-term exposure to cannabis impaired brain activity,

with the damage continuing into adulthood

The study, published in the journal Neuropsychopharmacology, exposed young mice to the active ingredient in marijuana for 20 days.

It found that their brain activity was impaired, with the damage continuing into adulthood.

The past 20 years has seen major controversy about the long-term effects of marijuana, with experts divided over its long-term effects on teenagers.

Significantly higher incidence of psychiatric disorders

Previous research has shown that children who started using marijuana before the age of 16 are at greater risk of permanent brain damage, and have a significantly higher incidence of psychiatric disorders.

‘Adolescence is the critical period during which marijuana use can be damaging,’ said the study's lead author, Sylvina Mullins Raver, a PhD candidate at the University of Maryland School of Medicine.

‘We wanted to identify the biological underpinnings and determine whether there is a real, permanent health risk to marijuana use.’

The scientists began by examining cortical oscillations in mice. Cortical oscillations are patterns of the activity of neurons in the brain and are believed to underlie the brain's various functions. 

These oscillations are very abnormal in schizophrenia and in other psychiatric disorders. 

VIDEO: Scientists explain how cannabis damages the teenage brain. 2:40

The scientists exposed young mice to very low doses of the active ingredient in marijuana for 20 days, and then allowed them to return to their siblings and develop normally.

‘In the adult mice exposed to marijuana ingredients in adolescence, we found that cortical oscillations were grossly altered, and they exhibited impaired cognitive abilities,’ said Raver. 

‘We also found impaired cognitive behavioural performance in those mice. The striking finding is that, even though the mice were exposed to very low drug doses, and only for a brief period during adolescence, their brain abnormalities persisted into adulthood.’

'The striking finding is that, even though the mice were exposed

to very low drug doses, and only for a brief period during

adolescence, their brain abnormalities persisted into adulthood.’

According to the research team, there is a group of people who have a genetic susceptibility to

developing schizophrenia. Adding weed to the mix during adolescence could be the trigger that

causes it to develop, permanently impairing brain function and cognition

The scientists repeated the experiment, this time giving marijuana to adult mice that had never been exposed to the drug before. 

Their cortical oscillations and ability to perform cognitive tasks remained normal, indicating that it was only drug exposure during the critical teenage years that impaired brain activity. 

‘We found that the frontal cortex is much more affected by the drugs during adolescence,’ said Keller. ‘This is the area of the brain controls executive functions such as planning and impulse control. It is also the area most affected in schizophrenia.’

Keller now wants to know whether the effects can be reversed. ‘We are hoping we will learn more about schizophrenia and other psychiatric disorders, which are complicated conditions,’ he said.

‘These cognitive symptoms are not affected by medication, but they might be affected by controlling these cortical oscillations.’

CANNABIS DESTROYS YOUR GET-UP-AND-GO

A separate study by Imperial College London last month revealed that long-term use of cannabis destroys dopamine, the feel-good chemical in the brain that inspires a spirit of get-up-and-go.

Previous research has suggested taking marijuana can lead to individuals becoming withdrawn, lethargic and apathetic.

The cannabis users in the study published in Biological Psychiatry had all experienced psychotic-like symptoms while smoking the drug such as strange sensations or having feelings of paranoia.

The researchers expected their dopamine production might be higher since this has been linked with psychosis - but instead found the opposite.

The cannabis users had their first experience with the drug between the ages of 12 and 18 and the researchers believe the drug could be the cause of the difference in dopamine levels.

'Cannabis is an illegal drug and there is mounting evidence the idea of it being a harmless herb is not true,’ said Dr Michael Bloomfield, of Imperial College London.

'When people stop taking cannabis it seems the brain can slowly go back to producing pretty normal levels of dopamine.

'Cannabis has effects on the brain and it’s important people can make an informed decision.'

Is Your Teen Smoking Pot? Is She Still Sane?

Turns out getting stoned on marijuana carries much more dire consequences for teenagers than for adults — at least if you’re a rat and part of a new study released Monday by researchers in London.

Researchers at Western University’s Schulich School of Medicine & Dentistry have published a study that shows that the psychoactive component of marijuana caused long-term harm on the adolescent brains of rats, producing changes similar to what is found in schizophrenia.

“Adolescence is a critical period of brain development and the adolescent brain is particularly vulnerable,” said Steven Laviolette, a professor in the departments of anatomy and cell biology, and psychiatry. “Health policy makers need to ensure that marijuana, especially marijuana strains with high THC levels, stays out of the hands of teenagers. In contrast, our findings suggest that adult use of marijuana does not pose substantial risk.” (of Schizophrenia)

After adolescent rodents were exposed to delta-9-tetrahydrocannabinol (THC) – the psychoactive component in marijuana – researchers found substantial and persistent behavioural, neuronal and molecular changes that are identical to neuropsychiatric conditions, such as schizophrenia.

Adolescent rodents with THC exposure were socially withdrawn, and had increased anxiety, cognitive disorganization and abnormal levels of dopamine – all factors present in clinical populations of schizophrenia. These changes continued into early adulthood, well past the initial exposure.

Adult rodents showed no harmful long-term effects, though both adolescents and adults exposed to THC experienced deficits in social cognition and memory.

As suggested in previous posts, aside from the risks of developing Schizophrenia, estimated at 1 in 6 for kids under 16, there are other consequences I have observed that science is just starting to get a grip on. That is the complete cessation of the maturing process for regular users. People who start using pot regularly, say weekly, at 15, will often continue to act, dress, talk, and think like a 15 year old. It may contribute to the epidemic of adults who still talk and act like adolescents, for instance. Michael Jackson used to mainline THC at night to get to sleep.

With the common use of marijuana by teenagers and the federal government’s move toward legalizing marijuana, researchers say that pot should be kept out of the hands of teens.

“Our research improves our knowledge of how adolescent exposure to THC may lead to the onset of schizophrenia in adulthood,” lead author Justine Renard said. “With the current rise in adolescent cannabis use and the increasing THC content in newer cannabis strains, it is critically important to highlight the risk factors associated with exposure to marijuana, particularly during adolescence.”

Researchers identified and performed tests in areas of behaviour that are commonly observed in schizophrenia and other neuropsychiatric disorders, such as social interaction, motivation and cognition, exploratory behaviours, levels of anxiety, cognitive disorganization (the inability to filter out unnecessary information), and various neuronal and molecular changes.

The study was published online in the January issue of Cerebral Cortex.

Smoking Strong Cannabis ‘Can Lead to Brain Damage,’ Study Finds

© Steve Dipaola / Reuters

Smoking extremely strong cannabis can lead to “significant” brain damage, a King’s College London study suggests.

The study, published in the journal Psychological Medicine, found that “skunk” cannabis damages the corpus callosum, a bundle of neural fibers that allows communication between the brain’s left and right hemispheres.

The two sides of the brain have very different functions. For instance the right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body. While the Bible says, "do not let the left hand know what the right hand is doing", it is speaking metaphorically. In reality, coordination between the two sides of the body is highly recommended. And there are many other reasons the two sides of the brain should be communicating.

In Holland, where marijuana is legally sold in cafes, skunk has been reclassified as a hard drug and is therefore illegal.

The illegal drug contains high levels of tetrahydrocannabinol (THC), the chemical responsible for the high users receive.

"It has long been known that people with a psychotic illness such as schizophrenia are far more likely to smoke both cannabis and tobacco,” Marjorie Wallace, the chief executive of the mental health charity SANE, said.

She added that scientists believe there is a direct link between cannabis and the levels of dopamine, which is the (the chemical messenger in the brain which is related to psychotic experience).

Regular use of the substance can lead to more harm, according to the research.

Frequently smoking the drug could trigger mental health issues, hallucinations and slow down brain activity.

Researchers examined 56 patients who reported having had a psychotic episode and 43 healthy volunteers.

The average age of healthier participants was 27 while the average age of psychotic patients was 29.

Previous studies highlighted much higher incidents of psychosis among teenagers smoking pot than adults. This study, while not determining incidents of psychosis does indicate that it does occur in adults, as well as the damage to white matter.

Lead researcher Dr Paola Dazzan, from the Institute of Psychiatry, Psychology and Neuroscience at King's College London, said: “We found that frequent use of high potency cannabis significantly affects the structure of white matter fibers in the brain, whether you have psychosis or not.

“This reflects a sliding scale where the more cannabis you smoke and the higher the potency, the worse the damage will be.”

Co-author Dr Tiago Reis Marques said: “This white matter damage was significantly greater among heavy users of high potency cannabis than in occasional or low potency users, and was also independent of the presence of a psychotic disorder.”

Legalizing pot

Commenting on the findings, freelance journalist Rhiannon Lucy Cosslett said legalizing the drug would give users “far greater control and choice” over the strength of what they smoked.

More than two million people in Britain smoked cannabis last year. A private analysis by the Treasury found that legalizing cannabis would raise tax revenues worth hundreds of millions of pounds and result in huge savings for the criminal justice system.

In August, government ministers debated a petition signed by 200,000 people calling for the legalization of cannabis. Its prohibition was upheld, however.