Marijuana makes rats lazy, less willing to try cognitively demanding tasks

THC makes rats lazy, less willing to try cognitively demanding tasks

New research from the University of British Columbia suggests there may be some truth to the belief that marijuana use causes laziness— at least in rats.

The study, published today in the Journal of Psychiatry and Neuroscience, found that tetrahydrocannabinol (THC), the main psychoactive ingredient in marijuana, makes less willing to try a cognitively demanding task.

"Perhaps unsurprisingly, we found that when we gave THC to these rats, they basically became cognitively lazy," said Mason Silveira, the study's lead author and a PhD candidate in UBC's department of psychology. "What's interesting, however, is that their ability to do the difficult challenge was unaffected by THC. The rats could still do the task— they just didn't want to."

For the study, researchers looked at the effects of both THC and cannabidiol (CBD) on rats' willingness to exert cognitive effort.

They trained 29 rats to perform a behavioural experiment in which the animals had to choose whether they wanted an easy or difficult challenge to earn sugary treats.

Under normal circumstances, most rats preferred the harder challenge to earn a bigger reward. But when the rats were given THC, the animals switched to the easier option, despite earning a smaller reward.

When they looked at the effect of CBD, an ingredient in marijuana that does not result in a high, researchers found the chemical did not have any effect on rats' decision-making or attention. CBD, which is believed to be beneficial in treating pain, epilepsy and even cancer, also didn't block the negative effects of THC.

"This was surprising, as it had been suggested that high concentrations of CBD could modulate or reduce the of THC," said Catharine Winstanley, senior author of the study and an associate professor in UBC's department of psychology. "Unfortunately, that did not appear to be the case."

Given how essential willingness to exert cognitive effort is for people to achieve success, Winstanley said the findings underscore the importance of realizing the possible effect of cannabis use on impairing willingness to engage in harder tasks.

While some people view marijuana as a panacea that can cure all ailments, the findings also highlight a need for more research to determine what THC does to the human brain to alter decision-making. That could eventually allow scientists to block these effects of THC, allowing those who use medical to enjoy the possible benefits of cannabis without the less desirable cognitive effects.

At the beginning of each behavioural experiment, rats chose between two levers to signal whether they wanted an easy or hard challenge.

Choosing the easy challenge resulted in a light turning on for one second, which the rats could easily detect and respond to by poking it with their nose, receiving one sugar pellet as a reward. In the more difficult challenge, the light turned on for only 0.2 seconds, rewarding the rat with two sugar pellets if they responded with a nose poke.


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Aug 24, 2016
As is usually the case, there are no statistics to indicate the degree of difference. So let's say you are a pot smoker reading this article. You freak out (and I do mean freak out). But if reading of the source material indicates that the degree of difference was 1%, you eat another brownie because that's no big thing.

For the umpteenth time I would request that authors provide statistics.

PS. I suppose the pot smoker is not going to read the source material.

Aug 24, 2016
This is interesting. Of all the effects that Marijuana has on the brain, I would have to say that one that cannot be disputed is that Marijuana users have reduced Ambition. This study seems to relate to that. Just take the easy way out, man. Go with the flow.

Aug 24, 2016
Maybe they are like me, I'm the laziest person on the planet. I always choose what is simplest. Juz say'n. especially when i'm high

Aug 24, 2016
I'm sure there will be more mouse-sized brained comments like krundoloss gave to us. His/her ambition is to troll and to make assumptions. Instead of knowing apparently he/she prefers to imagine that everyone using cannabis is the same. That it is not possible to get A's in college level course work, a degree, and, for example, graduate as a computer engineer and work 20+ years making lots of $$ to raise children and have a happy home.

Good luck to you.

Aug 24, 2016
The rats could still do the task— they just didn't want to

Key point of the article, cognitive function is still perfectly intact.

Aug 24, 2016
Ibuprofen blocks the negative aspects of marijuana on memory, this has already been shown by testing. I'm curious why, and if this is a cross-over they will look at? (They, meaning someone sometime. Probably not this crew, they won't read this haha)

Aug 24, 2016
Dude, even a *lab rat* isn't going to harsh a fine buzz by *working*.
I bet these rats are glad they're not in the control group.

Perform the same study with alcohol, and you'll almost certainly find the same result: challenging tasks are avoided. Amphetamines, though: you get busy on amphetamines.

RMQ
Aug 24, 2016
oh very intelligent, marijuana causes less ambition... let´s see if we can recall the following list of stoners:

Bob Dylan
Snoop Dog
Bob Marley
John Lennon
John Bono (U2)
Eminem
Oliver Stone
Woody Harrelson
Arnold (I have him in pictures smoking, and he is so little ambitious, that I do not need to add his last name!)
Richard Feynman
Oliver Sacks
Carl Sagan
Michael Pollan
William Shakespeare
Michael Jackson

Now, who did the research, I can´t remember her freaking name! why??? because she has not done enough!!!

AND ambition is TODAY a virtue, it was a vice until the beginning of the XX century. So reducing ambition is a very good thing.

Aug 24, 2016
..
Richard Feynman
Oliver Sacks
Carl Sagan
...

All scientists who died of cancer or precancerous disease before their time. Both Sagan and Feynman were around 70 years old. It is not clear that marijuana ever helped with their scientific works.

Aug 24, 2016
Hey I am not against it, nor do I judge anyone who does it, I used to do it, and I'm just saying that regular users have a tendency to have less ambition. Although it is so prolific that super-ambitious people have done it and of course it didn't slow them down because they are super-ambitious anyway. And Snoog Dogg, wow he impresses the hell out of me to do what he does so well and smoke so much weed at the same time. Like get stoned out and go on an Interview on late night TV. And BendBob, we sound alot alike LOL. We should hang out, LOL

Aug 24, 2016
Key point of the article, cognitive function is still perfectly intact.


At least for simple tasks like a reaction game. Other studies on humans show impaired ability up to 24 hours yet higher self-assesment scores, pointing to a dunning-kruger type effect where the person is dumber yet thinks they're smarter because they don't understand or notice what went wrong.

Perform the same study with alcohol, and you'll almost certainly find the same result: challenging tasks are avoided.


Quite the opposite. Pay me a penny for every time some drunk guy goes "I can do that"... alcohol is dis-inhibitive and in small amounts actually makes people more creative.

Aug 24, 2016
RMQ ----- Your list is full of musicians, or those in a creative art that can sometimes be helped by marijuana.

RMQ
Aug 24, 2016
Feynman died of cancer for doing research with radioactive materials....

And not sure 3 is enough to do statistical analysis of that, especially when the life expectancy in the USA was close their age at death. Probably they did not smoke good quality cannabis since the republicans were trying to destroy it.... because Willie Nelson is doing really well... lol

I am waiting for your scientific work pal.... it will be amazing I am sure

I forgot in the list at Kevin Spacey, great actor.

Aug 24, 2016
Also, don't call me a troll. I do not attack people, I just offer comments and debate points, but I never try to put others down. Frankly I think its sad when people want to anonymously insult others. Just make your point, but don't attack others.

RMQ
Aug 24, 2016

And if it reduces cognitive abilities, how come when they do analysis of the lyrics of all songs every published, the songs with the highest word variability are produced by the men who smoked marijuana all the time?

At the head of the list:
Eminem, he was the first place, I expected Bob Dylan when I started reading the research article about that.
Snoop Dogg
Bob Dylan, obviously
Jay Z
Do I need to continue?

I am sure the skeptical will come on saying that they wrote the music while sober... right

And science is not creative? lol.....

While I was taking a seminar visiting at the MIT, I went to seek for a buddy one day at his room, and the newspaper was on his doorstep, the main title said that Cambridge Mass and Berkeley Ca were the two cities in the USA with the highest consumption of cannabis.... no surprise.

The guy I was looking for that day grows his own cannabis. He works for the Air force, NASA and the department where he does research...

RMQ
Aug 24, 2016
My other friend, graduated from Berkeley in physics, started smoking marijuana at age 11. But as I tell my students all the time, he grew without watching ever television, he had a library of few thousands books instead... it is suspicious we don´t see much research on how television does make people retarded, lazy, depressive, fat, etc.

My other friend is a top weapon designer in the USA.... big bong hitter.

Oh, I forgot Phelps destroyed his body with cannabis. Oh, I forgot that he only smoked cannabis once, the day his "friend" took that picture.... right

No offense, but there is a lot of stupidity in the USA, trump is not coincidence.

Aug 24, 2016
"While some people view marijuana as a panacea that can cure all ailments..."
Strawman argument much? I wonder if there is any of that thing called BIAS behind this article and research.
Funny how you never see the actual scientific name of cannabis in these articles, always use the prohibition name with racist roots.
Lastly, it's completely nonsensical to use mice and rats in these studies. We already know it's safe for humans, so why not research on humans? Afraid of what you may find?
Truth: the longer we keep lying to our children about cannabis being a class 1 narcotic the longer youths will keep overdosing on more serious drugs. Heroin use is surging right now because our poor education mentality that weed is right up there with heroin (that can actually kill on first use).

Aug 24, 2016
Well RMQ, your point is well taken. It definitely affects different people in different ways. My sister used to do it and clean her whole house. While I would do it and play a video game or watch a movie, it didn't motivate me. Although I could do it and zone out while lifting weights. But I wouldn't dare do it and go to work. Then there are people that can, perhaps they have a more powerful, fast paced brain and the buzz helps them focus. I would say that marijuana has the effect of a person holding onto a thought longer than they normally would, if you know what I mean.

RMQ
Aug 24, 2016
kundroloss I am impressed that you are sensitive to rational arguments. Very hard to find nowadays. You sound more intelligent than me.

You give me hope in the future :)

Aug 25, 2016
how come when they do analysis of the lyrics of all songs every published, the songs with the highest word variability are produced by the men who smoked marijuana all the time?


Because THC in large amounts is known to produce effects similiar to schitsophrenia, involving symptoms of disjointed and confused thoughts and weird associations, resulting in a kind of word salad.


Aug 25, 2016
Back to the hard experimental details, taking the easy test for one sugar treat is the optimum strategy - if both options are available all the time (or available at a rate the exceeds the need to consume them) .
A better test would have given a more valuable treat, like a cashew nut, rather than two easy treats. .

Aug 25, 2016
"What's interesting, however, is that their ability to do the difficult challenge was unaffected by THC. The rats could still do the task— they just didn't want to."


It is our anthropomorphic ideas being inserted here. Does the rat no longer "desire" to do the harder task? Or could it be something else? An animal on a drug may not behave as a human on a drug, they may feel as though they are sick, where as a human may just roll with it and call it a good time. I bet if you did the same experiment with Rats that have a cold or some other temporary illness, that the behavior would be similar.

Aug 26, 2016
As is usually the case, there are no statistics to indicate the degree of difference. So let's say you are a pot smoker reading this article. You freak out
No, you give up half way through because why bother? And you forgot what you were reading about anyway.
My other friend is a top weapon designer in the USA.... big bong hitter
Big bongs are not weapons. They only look like weapons.

Aug 28, 2016
I guess the people with brains who use pot hope it doesn't drive them below 100 IQ?. For most avid pot abusers, that's not a concern.

Aug 28, 2016
..
Richard Feynman
Oliver Sacks
Carl Sagan
...

All scientists who died of cancer or precancerous disease before their time. Both Sagan and Feynman were around 70 years old. It is not clear that marijuana ever helped with their scientific works.


Plus Sagan went from being a productive scientist to a sack-cloth wearing kook who acted so weird Johnny Carson stopped asking him on his TV show. Steve Jobs also died early of cancer and was a known pot abuser.

Aug 28, 2016
Curiously it is assumed that the rats exhibited the well know amotivational syndrome, but did not exhibit the far more well known increase in appetite. Stoners may appear lazy but not too lazy when it comes to the appetite increase. It's studies like this that invite ridicule.

Aug 31, 2016
Common case of oversimplifying. It seems lethargy from pot can occur at some times but be offset by greater activity at at another time. The idea of 'choosing a lower cognitive load' can even be a better choice sometimes, free-up mental resources, and can come with a shift to 'other modes', like 'more creative, less cognitive, more spontaneous, less methodical. Pot can sometimes increase cortisol activity, making one more energetic. But depends on frequency of use it seems. Pot can remove creative inhibitions which is a good thing, but can increase cognitive aversion (as mentioned here) and sometimes increase social inhibitions, or at least provoke social anxiety (the 'paranoia' affect). The bottom line is that it DEPENDS on the individual differences in response and changes and use patterns. Assigning such a characteristic broadly and simple trait without context is stupid. it's myopic. I'm not endorsing or defending pot use, just giving a little more complete context.

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