Does smoking a joint make you feel a little bit lazy? According to new research, when your "Reefer Madness" turns into "Reefer Can't-get-off-the-couch," it could be because the cannabis is suppressing your ability to synthesize dopamine--the neurotransmitter associated with the pleasure of eating chocolate, and increasingly, motivation.
In an effort to study the (controversial) link between cannabis use and psychosis, researchers from three London universities examined the brains of pot smokers for differences in dopamine levels, since abnormal dopamine activity is associated with psychotic symptoms, especially schizophrenia. Their work is published online in Biological Psychiatry.
Using PET scans, the study looked at the brains of 19 regular cannabis users who had started smoking pot as teens, and had experienced psychosis-like behaviors under the influence of the drug--including perceptual distortion and paranoid ideas like "people can put thoughts into your mind" and "you can sense an evil presence around you, even though you cannot see it." The control group had used cannabis fewer than 10 times in their life, and hadn't used it at all in the three months prior to the study.
Though the researchers hypothesized that habitual pot users would experience increased dopamine production, since that has been linked with psychosis, they found that regular (at least weekly) cannabis users actually had a reduced capacity to synthesize dopamine. A causal relationship couldn't be proven, but those who started smoking earlier or smoked more had the lowest dopamine levels. The frequency of psychosis-like symptoms didn't have an effect on dopamine.
"Our ﬁndings of reduced dopamine synthesis capacity in dependent subjects may reﬂect a 'blunted' dopamine system," the authors write.
This lack of dopamine could possibly be the underlying reason as to why marijuana doesn't exactly turn people into go-getters, the authors suggest: Without the drive of dopamine, apathy reigns.
Interesting. So since increased dopamine is associated with increased psychosis, maybe the slightly higher numbers of psychotic pot smokers are self medicators.
Well we didn't confirm that cannabis makes you less motivated. There's other evidence indicating that. Also, given the evidence that cannabis increases dopamine in the short-term, our finding that long-term cannabis use is associated with decreased dopamine - wasn't that obvious to us - but it does seem to make sense...
I don't think the link between cannabis and psychosis is that controversial - my impression is that the controversy lies in just how much it increases risk of psychosis. Certainly the evidence suggests that the younger people are when they start smoking cannabis and the more regularly they smoke, the higher the risk of mental health problems.. Also, for a study using PET - having 38 subjects in total is actually relatively large...
The self-medication idea is really interesting - and it needs further research.
LOL. I had a science professor that once warned about reading PopSci articles. They can make you angry.
This was a small study done on people that had experienced psychosis in their teens... and now used regularly (probably to self medicate). I'm not sure how that indicates marijuana causes a dopamine issue in regular users.
"19 regular cannabis users who had started smoking pot as teens, and had experienced psychosis-like behaviors under the influence of the drug"
Does not equal all cannabis users.
This is really bad science and the fact that the staff would rather put up pictures from the 1940's and use weasel words rather than analyze the science is ... predictable.
angryjack says this is a big load... the results of this 'study' may be true for the majority, who are quite stupid, to put it bluntly, but it certainly does not apply to mois... it is disheartening to see that the popsci magazine i grew up with has turned to sensationalism to in the vain hope to attract comments from the public. comments that only serve to justify the ads to the right of the screen and nothing more.
More nonsense from prohibitionists who make very well paid livings keeping cannabis illegal? 17,000 medical research studies have been done on cannabis, making it one of the plants we know more about than any other. These kind of extremely limited studies pop up on demand with predictable regularity every time the prohibitionists see gains toward cannabis legalization. Sadly, everyone of them have already been disproved. I say, "sadly", because we US Taxpayers are being forced to fund these made to order results by the US Govt which stands to lose power, & govt jobs oppressing a plant that is the cure for cancers, & over 100 ailments. 19 people where involved in the study & it came from offshore. Typical, as they usually come from Australian researchers known for selling their bona fides for enough money to give the buyer a foregone conclusion. And, the result is cannabis, they call Marijuana, will make you go blind, cut off your brother's arm, or some such nonsense. It's time every American voter right their US Congressman, or woman, & demand the legalization of cannabis, outright. Cannabis is everywhere, thanks to the prohibitionists making it so popular with lies that people quickly find out are agenda driven. Not one user has ever been proved to have died from cannabis. Plus, the NIDA says caffeine (coffee) is more addictive than cannabis. There are so many famous successful people who use cannabis on a regular basis that this fact alone proves this so called study about cannabis users being slackers is a lie. So, some cannabis users are slackers. Sp what? The last three US Presidents admit to using cannabis, & so did George Washington, & Thomas Jefferson. Big deal that prohibitionists use stereotypes to justify their fat paychecks for keeping cannabis banned. 70-85% of US voters want cannabis legalized, depending on the State they live in. Look guys, we see through your endless scare tactics propaganda that's been disproved every single time without exception. So, give it a rest, already. Your like the boy who cried, "Wolf!" so many times no one with any knowledge of your tricks believes you any longer. You're only hurting your cause, & keeping a proved life saving medicine out of the hands of patients who suffer for lack of access to it. Cannabis was used in 50% of all American made medicines with extracts of up to 40% potency.Before racists, radical evangelicals,& pharmaceutical companies who pushed far more profitable synthetic dangerous prescription drugs joined together with former alcohol prohibition agents to declare war on cannabis users for their own profit. No one ever died from using cannabis, & it worked to treat diseases safely, & it still does. You people are evil for not only keeping people in needless suffering. You're worse,for putting patients in prison for using a plant that is God-given relief from the agonies of life some have to live with due to no safe medicine existing that does what cannabis does. I'll pray for you to e enabled to see the Word,, like so many former drug warriors have who now work with LEAP.cc to end the horrible war on some drug users. By far, the most disturbing thing about these endless diversionary article is the fact that the MSM picks up these stories & spreads them far & wide like fine manure, giving growth to even wilder weeds with nasty thorns that deprive the suffering from gaining relief. Shame on you, & may God send you wisdom to see that you are doing the work of evil men who joined together over 70 years ago to profit from causing Americans to suffer
PopSci's own headline is biased: Science Confirms The Obvious. Where is PopSci's peer reviewed documentation that this extremely small study is accurate? Who are the well respected researchers in this field of science who have lauded the construction of this study? So, PopSci has given into the MSM rush of judgment & thrown out their credentials as a source of information that is being studied, not concluded. I am ashamed of PopSci, & for my 50 years of being a faithful reader who even chose the name popscifan123 as a way to compliment your organization. Boo! And, goodbye, forever for your lack of professionalism & objectivity.
Wouldn't this imply that people with dopamine production issues (re: people with psychosis) will see changes in dopamine levels from marijuana? How can the reaction of anomalous people be applied to typical people without any recognition that the test subjects were inherently anomalous?
I don't think it is good science to draw conclusions about a phenomenon as complex as motivation by only examining one parameter, i.e. dopamine production. It is well-established that artists and even some scientists (Kary Mullis, Carl Sagan) have used various drugs (including herb) recreationally for inspiration. I wonder if the authors ever asked themselves whether inspiration can lead to motivation? I think the answer is yes... but when you only look at teens whose background we know nothing about other than that they had been smoking herb, then you are clearly not practicing good science. Perhaps the authors could have explained the social motives associated with this study before making rash conclusions?
Like any substance we put it our bodies, it will change the way your body functions depending on the amount of the substance input. Another major factor is how your body and brain processes substances such as THC and the other cannabinoids found in Marijuana. For example, people with ADHD will typically have very different affects from medication than most other people simply because their brains are wired differently, therefore chemical compounds interact with the brain's chemistry differently. Other things to take into consideration are people with high drug tolerances; race - certain races may have more extreme effects, others may have lesser towards different substances; even physical and mental health play key factors in how a person responds to different drugs.
I for one consider myself a highly functional stoner. I do have ADHD, and for me marijuana actually allows me to concentrate much more effectively, increases my motivation, not decreases it, and provides a much more "clear minded" feeling. It is a drug, just like so many others, including alcohol which once had a very medicinal use, not much any more, or even methamphetamines for those who need it. Used responsibly its a great substance for both medicinal use, and recreational use for those of us old enough to consume it, just like alcohol.
Had the marijuana raised dopamine levels, they would have reported that it causes psychosis, but it did the opposite of what they expected, so they reported that it lowered motivation.
So why isn't the more astonishing discovery that motivation is a form of psychosis not being reported?
It's been my experience that it definitely interferes with people's ability to communicate and comprehend.