Cannabis Abuse Alters Activity of Brain Regions Linked to Negative Emotion

Summary: Researchers report brain alterations associated with heightened feelings of negative emotion and alienation in people who have a dependence on cannabis.

Source: Elsevier.

Young people with cannabis dependence have altered brain function that may be the source of emotional disturbances and increased psychosis risk that are associated with cannabis abuse, according to a new study published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. The alterations were most pronounced in people who started using cannabis at a young age. The findings reveal potential negative long-term effects of heavy cannabis use on brain function and behavior, which remain largely unknown despite the drug’s wide use and efforts to legalize the substance.

The study, by Drs. Peter Manza, Dardo Tomasi, and Nora Volkow of the National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland, assessed resting brain activity data from the Human Connectome Project of 441 young adults, and compared a smaller set of 30 people who met criteria for cannabis abuse with 30 controls. People with heavy cannabis use had abnormally high connectivity in brain regions important for reward processing and habit formation. The same regions have also been pegged in the development of psychosis in previous research.

“These brain imaging data provide a link between changes in brain systems involved in reward and psychopathology and chronic cannabis abuse, suggesting a mechanism by which heavy use of this popular drug may lead to depression and other even more severe forms of mental illness,” said Dr. Cameron Carter, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.

a man smoking
The brain alterations were also associated with heightened feelings of negative emotionality, especially alienation, where one feels a sense of hostility or rejection from others. The link points to a potential biological mechanism for why feelings of alienation are often profoundly increased in people with cannabis dependence. NeuroscienceNews.com image is in the public domain.

The brain alterations were also associated with heightened feelings of negative emotionality, especially alienation, where one feels a sense of hostility or rejection from others. The link points to a potential biological mechanism for why feelings of alienation are often profoundly increased in people with cannabis dependence.

“Interestingly, the hyperconnectivity was strongest in the individuals who began using cannabis in early adolescence,” said Dr. Manza, which lines up with reports of a higher risk of psychiatric problems when cannabis use begins early in life. Adolescence is a critical period of brain development, making early use of cannabis particularly detrimental. According to Dr. Manza, the measurement of resting brain activity is a relatively easy and non-invasive procedure, so the approach could be a useful measure for tracking the development of psychiatric symptoms with cannabis use.

About this neuroscience research article

Source: Elsevier
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Full open access research for “Subcortical local functional hyperconnectivity in cannabis dependence” by Peter Manza, Dardo Tomasi, and Nora D. Volkow in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. Published online November 21 2017 doi:10.1016/j.bpsc.2017.11.004

Cite This NeuroscienceNews.com Article

[cbtabs][cbtab title=”MLA”]Elsevier “Cannabis Abuse Alters Activity of Brain Regions Linked to Negative Emotion.” NeuroscienceNews. NeuroscienceNews, 16 January 2018.
<https://neurosciencenews.com/cannabis-negative-emotion-8320/>.[/cbtab][cbtab title=”APA”]Elsevier (2018, January 16). Cannabis Abuse Alters Activity of Brain Regions Linked to Negative Emotion. NeuroscienceNews. Retrieved January 16, 2018 from https://neurosciencenews.com/cannabis-negative-emotion-8320/[/cbtab][cbtab title=”Chicago”]Elsevier “Cannabis Abuse Alters Activity of Brain Regions Linked to Negative Emotion.” https://neurosciencenews.com/cannabis-negative-emotion-8320/ (accessed January 16, 2018).[/cbtab][/cbtabs]


Abstract

Subcortical local functional hyperconnectivity in cannabis dependence

Background
Cannabis abuse has been associated with psychopathology, including negative emotionality and a higher risk of psychosis, particularly with early age of initiation. However, the mechanisms underlying this association are poorly understood. Because aberrant dopamine (DA) signaling is implicated in cannabis-associated psychopathology, we hypothesized that regular cannabis abuse (CA) would be associated with altered resting functional connectivity in dopamine midbrain-striatal circuits.

Methods
We examined resting brain activity of subcortical regions in 441 young adults from the Human Connectome Project, including 30 CA meeting DSM criteria for dependence, and 30 controls matched on age, sex, education, BMI, anxiety, depression, and alcohol/tobacco usage.

Results
Across all subjects, local functional connectivity density (lFCD) hubs in subcortical regions were most prominent in ventral striatum, hippocampus, amygdala, dorsal midbrain, and the posterior-ventral brainstem. As hypothesized, CA showed markedly increased lFCD relative to controls in ventral striatum (where nucleus accumbens is located) and midbrain (where substantia nigra/ventral tegmental nuclei are located) but also in brainstem and lateral thalamus. These effects were observed in the absence of significant differences in subcortical volumes, and were most pronounced in the individuals who began cannabis use earliest in life and who reported high levels of negative emotionality.

Conclusions
Together, these findings suggest that chronic cannabis abuse is associated with changes in resting brain function, particularly in dopaminergic nuclei implicated in psychosis but that are also critical for habit formation and reward processing. These results shed light on neurobiological differences that may be relevant to psychopathology associated with cannabis use.

“Subcortical local functional hyperconnectivity in cannabis dependence” by Peter Manza, Dardo Tomasi, and Nora D. Volkow in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. Published online November 21 2017 doi:10.1016/j.bpsc.2017.11.004

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  1. Having been a heavy cannabis user for many years, currently on an enforced break from use (due to being in a country where its not worth getting caught with it), I can certainly attest to its addictive nature, that it can indeed lead to social isolation and yes, depression.
    As the years go by, it’s become much harder to connect with other humans, get out and do things, and generally carry on with a ‘normal’ life. The time off it has seen me start to become much less agoraphobic, and open myself up to human connection (and general interaction) again.

    I don’t think cannabis is in any way evil, or bad, or should be illegal. But it does have creeping negative effects with heavy dependence, and can be very difficult to quit.

  2. Unfortunately this experiment is flawed, the reasons for behaviour problems could’ve been caused by all sorts of different reasons.
    Only way to be sure is a complete control experiment.
    In my opinion cannabis definitely help s with my personal issues. I don’t like being stoned thc isn’t for me. I’d prefer more of a cbd ratio to thc 70/30
    I blame life and poor parenting and the resultant experiences endured for behavioural problems and not a clearly medicinal plant for it.

  3. Why limiting it to young adults and not simply to adults who started using at an early age or impact of the number of years of cannabis use? These described symptoms exist in many adult users.

  4. The title is a lie, it doesn’t follow from the study. The study found some correlations, but not evidence of brain alteration nor evidence of causation. A good study exploring correlations should at least mention the other possible explanations: for example that people with altered brains are more likely to start using cannabis earlier or that a factor causing the explored brain alterations also causes people to use more/earlier

    1. If the use of cannabis is started in early life, it can cause these problems & in daily use.
      Besides that, I see it as a helpful tool for treating anxiety, sleep disorders, PTSD & pain….MOST DEFINITELY IN PAIN CONTROL.

      NO ONE HAS EVER OD’ED ON IT!
      Government is not giving the proper information out.
      Government is severely uneducated over the medical advantages of its use.

      Big pharma want in to make $ instead of to help …..

  5. I’ve met so many people who use this DRUG and they become very lies and vielent and so depending on this drug my sister has become anric

    1. Dude I don’t believe anything you’re saying you must b confused or pissed out of your head.
      What you seem to be suggesting is the effects from alcohol abuse heroin or crack withdrawal.
      In all the years and the hundred of cannabis users I’ve had the pleasure of sharing lifetime experiences with Not one has ever even remotely been violent or well maybe a few TALL STORIES WERE TOLD. Lol ? sorry if I’m being rude but are you foreign ? As in English not your first language??
      What does antic mean?
      Sorry my friend but YOU ARE VERY MISTAKEN ON EFFECT OF MARIJUANA.
      I’d bet my life on it, what ever they were smoking; it weren’t cannabis , probably a thistle or some man made shite made out of a chemistry set.
      Bitch please, send a sample in for verification or jog on the person that sold them….. sage and onion stuffing I guess….
      I Repeat; what your sister and all those poor souls that you believed were smoking Maryjane
      It wasn’t!!!

  6. bull if somke all the time high strain skunk more than 30 year s and no problems go to work every day

  7. The problem with this study is that they didn’t explore external factors in the patients lives that lead to cannabis use/abuse at an early age. What leads a youth to begin using cannabis at an early age to begin with? Are they struggling socially? Do they experience loneliness and isolation due to family problems or social problems and then turn to the outcasts and indulge in cannabis for acceptance? Correlation in this study doesn’t beget causation unless they can account for the external factors that lead to early use. If you want to stop kids from using cannabis it should be regulated like alcohol first, then the factors leading to early use should be examined. It’s hard to believe that the small sample size of 30 early and heavy users are well adjusted kids with good family and social lives who just somehow found a bag of grass on the sidewalk and became heavy users. Let’s try again. Also, nobody under 21 should use cannabis unless it is to treat a medical condition. We need a fair look that explores more than just one factor.

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