Cannabis - Page 2 of 3

Alcohol Or Cannabis: Which Is Worse For Brain Health?

Study of over 1,000 people’s brains tested whether alcohol or cannabis does the most damage.

Long-term alcohol use is more damaging to the brain than long-term cannabis use, new research finds.

The assumption among many scientists has been that cannabis use may be just as damaging to long-term health as alcohol.

But this new study of over 1,000 people’s brains suggests otherwise.

Alcohol use is linked to decreased gray matter size and lower white matter integrity, the researchers found.

Cannabis, though, had no link to reductions in these critical measures of brain health.

Professor Kent Hutchison, study co-author, is sceptical about the research suggesting cannabis is just as bad for the brain as alcohol:

“When you look at the research much more closely, you see that a lot of it is probably not accurate.
When you look at these studies going back years, you see that one study will report that marijuana use is related to a reduction in the volume of the hippocampus.
The next study then comes around, and they say that marijuana use is related to changes in the cerebellum or the whatever.
The point is that there’s no consistency across all of these studies in terms of the actual brain structures.”

While some suggest cannabis use can be beneficial, many scientists are hesitant.

Rachel Thayer, the study’s first author, said:

“Particularly with marijuana use, there is still so much that we don’t know about how it impacts the brain.
Research is still very limited in terms of whether marijuana use is harmful, or beneficial, to the brain.”

The study involved people with a variety of different alcohol and cannabis intakes aged 18-55.

Professor Hutchison concluded:

“…while marijuana may also have some negative consequences, it definitely is nowhere near the negative consequences of alcohol.”

The study was published in the journal Addiction (Thayer et al., 2017).

Regular Cannabis Use Reduces Creativity And Error Checking

Studies tested how cannabis use affects creativity, error detection and neurotransmitters.

Studies tested how regular cannabis use affects creativity, error detection and neurotransmitters.

Regular cannabis use is linked to worse creative thinking, new research concludes.

They also find it harder to spot their own mistakes.

The conclusions come from a series of studies carried out by psychologist Mikael Kowal.

Regular cannabis use

One of the studies tested people’s brainstorming abilities.

It showed that regular cannabis users performed worse.

Mr Kowal said:

“There is a widespread belief among users that these drugs enhance creativity.
This experiment disproves that belief.”

Another study tested how good people were at detecting their own mistakes.

Again, regular cannabis users performed poorly.

Mr Kowal said:

“It is important that we gather more knowledge about the effects of cannabis on a person’s ability to detect mistakes.
This can help with putting together a treatment programme for drug addiction.”

Dopamine disruption

In the long-term cannabis disrupts the activity of the neurotransmitter dopamine.

One sign of this is that regular users blink significantly less than non-users.

Mr Kowal concluded:

“More research is needed on the effects of cannabis and on the individual consequences it can have on mental functions.”

The studies are part of Mr Kowal’s PhD.

Cannabis Shown To Have This Mental Cost For First Time

Occasional cannabis users were tested along with those addicted to the drug.

Occasional cannabis users were tested along with those addicted to the drug.

A single ‘spliff’ is enough to reduce the motivation to work, new research finds.

It is the first study to show the problematic short-term effects of cannabis on motivation.

Dr Will Lawn, the study’s first author, said:

“Although cannabis is commonly thought to reduce motivation, this is the first time it has been reliably tested and quantified using an appropriate sample size and methodology.
It has also been proposed that long-term cannabis users might also have problems with motivation even when they are not high.
However, we compared people dependent on cannabis to similar controls, when neither group was intoxicated, and did not find a difference in motivation.
This tentatively suggests that long-term cannabis use may not result in residual motivation problems when people stop using it.
However, longitudinal research is needed to provide more conclusive evidence.”

The study involved people who used cannabis occasionally.

They were offered small amounts of money for performing a series of tasks involving pressing the space key on a computer keyboard.

Sometimes they had inhaled cannabis smoke beforehand, other times they inhaled a placebo that did not contain cannabis.

Professor Val Curran, a senior study author, said:

“Repeatedly pressing keys with a single finger isn’t difficult but it takes a reasonable amount of effort, making it a useful test of motivation.
We found that people on cannabis were significantly less likely to choose the high-effort option.
On average, volunteers on placebo chose the high-effort option 50% of the time for a £2 reward, whereas volunteers on cannabis only chose the high-effort option 42% of the time.”

A second study carried out a similar test on people who were addicted to cannabis rather than just being occasional users.

The addicts showed similar motivation levels to the control group.

So this study provided no evidence that cannabis affects motivation in the long-term.

The study was published in the journal Psychopharmacology (Lawn et al., 2016).

→ The effects of regular cannabis use on creativity.

The Illicit Drug That Removes Toxic Alzheimer’s Proteins

The neuroprotective effect of this common drug on Alzheimer’s.

The neuroprotective effect of this common drug on Alzheimer’s.

Compounds in marijuana could help to prevent Alzheimer’s disease, new research finds.

The compounds, which include tetrahydrocannabinol, can promote the removal of a toxic protein related to Alzheimer’s disease.

It could help to explain why exercise — which produces natural endocannabinoids — is also protective against Alzheimer’s.

Professor David Schubert, senior author of the study, said:

“Although other studies have offered evidence that cannabinoids might be neuroprotective against the symptoms of Alzheimer’s, we believe our study is the first to demonstrate that cannabinoids affect both inflammation and amyloid beta accumulation in nerve cells.”

The tests were carried out on neurons grown in the laboratory.

Researchers found that exposing these cells to THC — the active component of marijuana — reduced the levels of the toxic protein linked to Alzheimer’s.

It also eliminated the inflammatory response.

Dr Antonio Currais, the study’s first author, explained:

“Inflammation within the brain is a major component of the damage associated with Alzheimer’s disease, but it has always been assumed that this response was coming from immune-like cells in the brain, not the nerve cells themselves.

When we were able to identify the molecular basis of the inflammatory response to amyloid beta, it became clear that THC-like compounds that the nerve cells make themselves may be involved in protecting the cells from dying.”

It is now yet known if THC could provide a useful therapy against Alzheimer’s.

This would need to be tested in clinical trials.

However, one small trial has already found that medical cannabis oil containing THC can help people with the symptoms of dementia (Shelef et al., 2016).

This trial found a significant reduction in psychological and behavioural symptoms of dementia such as agitation, aggression, delusions and apathy.

The study was published in the journal Aging and Mechanisms of Disease (Currais et al., 2016).

Alzheimer’s image from Shutterstock

Here’s What Alcohol Plus Cannabis Does To The Brain

Alcohol plus cannabis is one of the most frequently detected combinations of drugs in car accidents.

Alcohol plus cannabis is one of the most frequently detected combinations of drugs in car accidents.

Alcohol and cannabis taken together may increase the effect of the cannabis, a new study finds.

This may be why, in car accidents, alcohol plus cannabis is one of the most frequently detected combinations of drugs.

Taking both drugs together significantly increases the levels of cannabis’ main psychoactive ingredient, THC (tetrahydrocannabinol) in comparison to taking cannabis alone.

For the research, 19 adults either took doses of cannabis or a placebo.

Both were combined with alcohol.

Tests demonstrated significantly higher levels of THC when the same amount of cannabis was taken with alcohol rather than with a placebo.

Dr Marilyn A. Huestis, the study’s first author, said:

“The significantly higher blood THC and 11-OH-THC [median maximum concentration] values with alcohol possibly explain increased performance impairment observed from cannabis-alcohol combinations.
Our results will help facilitate forensic interpretation and inform the debate on drugged driving legislation.”

The study was published in the journal Clinical Chemistry (Huestis et al., 2015).

→ The effects of regular cannabis use on creativity.

Cannabis user image from Shutterstock

The Long-Term Consequences of Marijuana Use For The Brain

Study reveals how long-term marijuana use affects the brain’s structure and function.

Study reveals how long-term marijuana use affects the brain’s structure and function.

Regular marijuana users have increased connectivity in their brains, despite having some gray matter loss in areas related to addiction, a study finds.

The research, published in the Proceedings of the National Academy of Sciences, is the first to use multiple brain scanning techniques to examine both the structure and function of the brain.

Dr. Sina Aslan, one of the study’s authors, explained:

“What’s unique about this work is that it combines three different MRI techniques to evaluate different brain characteristics.
The results suggest increases in connectivity, both structural and functional that may be compensating for gray matter losses.
Eventually, however, the structural connectivity or ‘wiring’ of the brain starts degrading with prolonged marijuana use.”

The study involved 48 adult marijuana users who used the drug, on average, three times a day (Filbey et al., 2014).

They were compared to 62 matched non-users of marijuana.

The researchers found that the pattern of changes in both connectivity and structure of the brain depended on when and how often the drug was used.

Increases in connectivity were greatest when people began to use the drug and, the more they used it, the greater those increases.

Over time, though, an area of the brain called the orbitofrontal cortex is smaller in long-term marijuana users.

This area is crucial in how we make decisions and is central to how to brain processes rewards.

Taken together, this may explain why long-term marijuana users often seem to be doing reasonably well: structural losses in one area are being compensated for by connectivity gains.

It may also explain why the studies on marijuana’s effects on the brain have been so varied — some saying there is little damage, others more alarmist.

Dr. Francesca Filbey, who led the study, said:

“To date, existing studies on the long-term effects of marijuana on brain structures have been largely inconclusive due to limitations in methodologies.
While our study does not conclusively address whether any or all of the brain changes are a direct consequence of marijuana use, these effects do suggest that these changes are related to age of onset and duration of use.”

We still don’t know, though, the long-term effects of occasional marijuana use or whether the changes revert back to normal after drug-use is stopped.

Dr. Filbey concluded:

“We have seen a steady increase in the incidence of marijuana use since 2007.
However, research on its long-term effects remains scarce despite the changes in legislation surrounding marijuana and the continuing conversation surrounding this relevant public health topic.”

This study provides a fascinating insight into a controversial area.

Image credit: ashton

How Cannabis Causes Paranoia

Cannabis study provides insight into how to treat serious mental disorders.

Cannabis causes short-term paranoia and it’s not related to memory problems, a comprehensive new study has found.

The researchers discovered that after being given the main psychoactive ingredient in cannabis, THC (Δ9-tetrahydrocannabinol), participants became anxious, developed low self-esteem and experienced unsettling changes to their perceptions (Freeman et al., 2014).

The study’s lead author, Professor Daniel Freeman, said:

“The study very convincingly shows that cannabis can cause short-term paranoia in some people.
But more importantly it shines a light on the way our mind encourages paranoia.
Paranoia is likely to occur when we are worried, think negatively about ourselves, and experience unsettling changes in our perceptions.”

There were 121 people taking part in the study, none of whom were suffering from mental illness, but who had used cannabis before.

Two-thirds of them were injected with THC, while the remainder were injected with a placebo.

The amount was equivalent to a strong joint.

Half the people who were given the drug experienced paranoid thoughts, compared with 30% in the control group.

On top of this there were a variety of other psychological effects of the THC:

thoughts echoing,
altered perception of time,
anxiety,
various changes in perception such as sounds being louder than normal and colours brighter,
lowered mood,
negative thoughts about the self,
and poorer short-term memory.

When they looked at the results statistically, they were able to estimate what was causing the paranoia.

It turned out that it wasn’t a poorer memory:

“The increase in negative affect and in anomalous experiences fully accounted for the increase in paranoia.
Working memory changes did not lead to paranoia.
Making participants aware of the effects of THC had little impact.”

The scientists think the study of how cannabis causes paranoia will help the treatment of mental disorders which included delusional states, like schizophrenia:

“The clear clinical implication is that reducing negative emotion in patients with delusions, eg, by reducing the tendency to worry, testing out anxious fears, and increasing self-confidence, will lead to improvements in paranoia.
Also, the identification, normalization, and reduction of subtle anomalies of experience (eg, by reducing triggers and learning to tolerate the confusing sensory experiences) are clinically warranted.” (Freeman et al., 2014).

Fascinatingly, some people in the control group who were given a placebo also acted stoned, and it was difficult to tell the difference Freeman explained:

“…the placebo produced extraordinary effects in certain individuals.
They were convinced they were stoned, and acted accordingly.
Because at the time we didn’t know who had been given the drug, we assumed they were high too.”

Image credit: Alistair Holmes

Brain Changes Associated With Casual Marijuana Use

Brain region involved in reward, learning, pleasure and impulsivity may be affected by light marijuana use.

Young adults who smoked marijuana at least once a week showed changes in two brain regions associated with motivation and emotion, a new study finds.

The study, published in The Journal of Neuroscience, compared the density, size and shape of the amygdala and nucleus accumbens in 20 marijuana users with 20 non-users.

The 18-25-year old marijuana users smoked the drug at least once a week, but were not dependent on it.

The comparisons between the two groups showed that the nucleus accumbens — an area involved in reward processing — was larger and a different shape in marijuana users.

Dr Carl Lupica, who studies drug addiction, commented:

“This study suggests that even light to moderate recreational marijuana use can cause changes in brain anatomy.
These observations are particularly interesting because previous studies have focused primarily on the brains of heavy marijuana smokers, and have largely ignored the brains of casual users.”

This study builds on previous research on animals showing that even relatively low doses of tetrahydrocannabinol (THC) — marijuana’s main psychoactive component — can cause structural changes in the brain.

This study comes soon after research which reviewed 120 studies on the effect of marijuana use on the teenage brain.

The conclusions of that report were that for those with particular vulnerabilities, like neuroticism and anxiety, marijuana is not as harmless as many assume.

Findings about the connection between marijuana use and very serious mental illnesses, like schizophrenia, have been unclear, with some saying it can be a causative factor in those who are vulnerable while others find little or no evidence.

Unfortunately, what we currently know about the effects of marijuana on the brain is mostly from heavy users of the drug.

This study hints, however, that even relatively causal use of marijuana may cause changes in the brain.

We don’t yet know what the implications of these changes are, but they certainly warrant further investigation.

→ The effects of regular cannabis use on creativity.

Image credit: Peter Briones

Marijuana Does Not Cause Schizophrenia

New study on marijuana use finds little evidence that the drug causes schizophrenia.

The study, published in Schizophrenia Research, and carried out at Harvard Medical School, compared families with and without a history of schizophrenia (Proal et al., 2013).

It comes in response to much research which has linked marijuana use with schizophrenia (e.g. Moore et al., 2007).

These previous studies, however, could not rule out the possibility that people who are prone to developing schizophrenia are also more likely to use marijuana.

In other words: marijuana may not cause schizophrenia, but it might be that people who are prone to developing schizophrenia are more likely to use marijuana. This would explain the link that’s been found in the studies.

In the new study, by comparing families with and without a history of marijuana use, the Harvard researchers were able to address this question.

They recruited four groups:

87 non-psychotic people who had used no drugs.
84 non-psychotic people who had used marijuana.
32 patients who had schizophrenia but hadn’t used drugs.
76 patients with schizophrenia who had used marijuana.

They then looked at the relatives of those with schizophrenia in comparison to the relatives of those in the control groups.

The results showed an increased risk of developing schizophrenia in the relatives of patients who already had schizophrenia, whether or not those patients used marijuana.

This study, then, finds no evidence that marijuana is associated with developing schizophrenia. The authors conclude that:

“…cannabis does not cause psychosis by itself. In genetically vulnerable individuals, while cannabis may modify the illness onset, severity and outcome, there is no evidence from this study that it can cause the psychosis.” (Proal et al., 2013).

Is it safe?

One study, of course, is not the end of this debate.

For one thing this study can’t tell us anything about the interaction between the genetic predisposition to develop schizophrenia and marijuana use.

Many researchers still believe that marijuana use may be a factor in the onset of schizophrenia in those who are at risk.

Certainly, there is plenty of other evidence out there that marijuana is not the totally safe drug that many teenagers perceive it to be.

→ Read on: Teen Myth: Marijuana is a ‘Safe Drug’.

Image credit: Eugenia Lyakhova

Teen Myth: Marijuana is a ‘Safe Drug’

New research challenges the common teenage view that marijuana is a ‘safe drug’ in comparison to alcohol and tobacco.

Especially among teens, there is perception that, in comparison to ‘dangerous’ legal drugs like alcohol and tobacco, marijuana is relatively safe.

Surveys suggest that one-third of high school seniors have tried pot in the last year and less than half of 17-year-olds believe the drug is harmful.

A new review of the evidence, however, to be published in Neuropharmacology, suggests the drug may have harmful consequences for the growing adolescent brain.

Hurd et al. (2013) reviewed data from more than 120 studies to examine the relationship between marijuana use and the teenage brain.

They find that marijuana may be harmful for a particular type of vulnerable adolescent, possibly leading to behavioural problems and addiction.

One of the study’s authors, Didier Jutras-Aswad explained:

“It is now clear from the scientific data that cannabis is not harmless to the adolescent brain, specifically those who are most vulnerable from a genetic or psychological standpoint. Identifying these vulnerable adolescents, including through genetic or psychological screening, may be critical for prevention and early intervention of addiction and psychiatric disorders related to cannabis use.”

While the research on the long-term effects of marijuana use, especially in vulnerable populations, is still relatively young, the warning signs are mounting:

A study of 1,037 individuals followed from birth found that persistent cannabis use was associated with cognitive decline over the years. More worryingly these problems continued even after drug use ceased (Meier et al., 2012).
A review of many studies on marijuana use has found that it can damage the encoding, storage, manipulation and retrieval mechanisms of memory (Solowij & Battisti, 2008).

Teenagers should be aware that, for those with particular vulnerabilities, like neuroticism and anxiety, marijuana is not as harmless as many assume.

Image credit: miggslives