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Does Cannabis Make You Grumpy?

January 13, 2016

One of my coworker's friends recently asked her whether cannabis can make its consumer "grumpy," because sometimes he wakes up cranky after an evening of smoking. His timing was serendipitous, as I chanced upon a study from December 2014 that examined the effects of marijuana use on "impulsivity and hostility in daily life."

For this study, researchers from the Yale University School of Medicine's Department of Psychiatry and Penn State University's Department of Psychology collaborated to better understand whether cannabis use affected consumers' daily experiences. They found 43 participants with no substance dependence and asked them to report on their alcohol consumption, tobacco use, recreational cannabis use, impulsivity, and interpersonal hostility for a period of 14 days. 

The participants were a mix of men and women who have previously consumed cannabis and had an alcoholic beverage at least once per week. They weren't substance dependent, nor did they use any substances aside from cannabis, alcohol, or nicotine. After a phone screening and intake interview, they completed a carbon monoxide test and provided urine samples before being trained on how to complete their daily assessments on a smartphone. 

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Each night, the participants were prompted to measure the following information:

  • Daily alcohol, tobacco, and cannabis use (how many drinks were consumed, how many cigarettes or cigars were used, and how many "hits" of cannabis were taken and the method of intake)
  • Daily impulsivity as logged by a 7-item short form survey using the "Barratt Impulsiveness Scale-Brief"
  • Daily interpersonal hostility in the form of a survey every time a subject had an interpersonal interaction lasting longer than five minutes

The data showed that impulsivity increased on days cannabis was used compared to days it wasn't used, and interpersonal hostility increased on use days as well. 

Research findings on cannabis and impulsivity
Click on the chart to enlarge it


According to the study's findings: 

"Our findings support a directional effect on marijuana use on increases in next day impulsivity, a result not previously described in the literature. This is consistent with prior research findings that occasional users of marijuana experience stronger effects of marijuana on attention and inhibition relative to chronic users (Theunissen et al., 2012)."

What's the science behind this conclusion? The researchers dive into that, too:

"Laboratory studies have found that individuals under the influence of marijuana displayed systematic changes in interpersonal behavior and experience, including a pattern of interpersonal withdrawal, hostility, and diminished interpersonal skills. Despite subjective reports of enhanced sensation and perception, individuals under acute administration of THC showed objective decreases in the number of interpersonal interactions engaged in and the expression of empathetic communications. This suggests that marijuana use has a significant impact on interpersonal behaviors, of which users are not aware. Additional research has found social-emotional deficits in marijuana users, and increases in hostility or aggression." 

The study reports that chronic cannabis consumers have anterior cingulate cortex (ACC) and amygdala deactivation in response to "subconscious presentation of emotional faces," compared to a control group displaying increased activation. The ACC plays a role in error monitoring, behavioral correction, and inhibition when responding to contextual or environmental changes, so a deactivation of the ACC and the amygdala could "manifest as inappropriate interpersonal responses or altered perceptions of interpersonal behavior in others." In other words, chronic consumption can be deactivating the part of your brain that keeps your stinkface reaction in check.

So what's the downside to being a grumpypus? Well, according to researchers, impulsivity is associated with a higher risk for mental health issues, addiction disorders, and risky behavior, while hostility can be tied to cardiovascular risk, stress-related health dysfunction, troubled intimacy, and other aggressive behaviors. 

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The study, however, is not without flaws. The sample size is incredibly small, and researchers were unable to observe any effects of alcohol use on impulsivity or hostility, despite citing previous studies that have identified such effects (to be fair, another study was cited that also failed to find alcohol effects on risk-taking behavior, though five minutes on YouTube should lend credence to the idea that alcohol and risk-taking behavior are often related). 

Second, the researchers conceded that "asking participants to rate their own behaviors may have promoted a level of self-awareness that subsequently impacts either interpersonal behaviors or ratings of behaviors," and that "future research should examine whether self-monitoring of interpersonal behaviors results in differences in actual behaviors." In other words, the participants could have been overly self-critical since they knew they had to log their daily behavior for this study. First, the researchers' primary predictor of interest was whether their subjects reported any cannabis use vs. specific doses, which, as we know, can vary considerably. 

Finally, and quite possibly most amusingly, "…individuals may have been intoxicated while completing the surveys and this may have biased the responses for same day effects. Future research should examine whether level of intoxication changes these effects." Translation: Our subjects could have been super drunk or super stoned or both, so their self-reported data could be skewed. 

So does cannabis make you grumpy or not? According to this study, yes, but as with all cannabis findings, more research is needed because the limited number of studies that exist are only able to tell us a partial story. Also, this study was narrow in its scope and flawed in its methodology, which is another reason why we need more research so we can test, re-test, and test some more until we're able to come to more confident conclusions. Re-scheduling cannabis would be a huge step in the right direction, as it would open up more research avenues. 

Time for you to weigh in! In your personal experience, have you noticed your mood turning sour after chronic cannabis consumption, or is the outcome of this study the only thing making you angry right now? 

Source: Ansell, E.B., et al., Effects of marijuana use on impulsivity and hostility in daily life. Drug Alcohol Depend. (2015),

  • FlunkedAgain

    I don’t know if it’s the weed or not, but I’m less tolerant of stupidity.

    I’m an Old man, who has used cannabis for over 40 years. Maybe it’s the aging process, after all the movie Grumpy Old Men wasn’t called Grumpy Old Stoners.

    • Allie

      That’s a film ready and waiting for Kevin Smith to get old enough.

    • Danyiel Romo Mendoza

      Maybe you are right. I came here looking if it was my now use of THC oil as a relaxant what is making me ironically stressed at other people. Maybe I am just getting old too.

  • Gabe B

    It’s funny because whenever Canabinoids hit my system I feel like I become LESS grumpy.

  • Mary Lucas

    This isn’t true at all! It’s alcohol that makes you grumpy. Cannabis relaxes you inside and out, while alcohol can make you aggressive especially after you’ve had too much. This is why people who are drunk are more likely to get into fights.

    • Kerry McGuire

      It makes me grumpy the next day. I guess it’s different for different people.

    • Mitchell Steven

      YES IT IS TRUE! l don’t drink smoked for 44yrs quit a month ago and stupid people, young people rude people l have a low tolerance FOR! And yes if you are rude to me l will light you up like a Christmas tree! 👹

    • nik lazio

      How can you determine that people’s direct experiences aren’t true? It wasn’t your experience. It doesn’t mean it’s not true. I haven’t drank alcohol for 3 years, I was a happy silly drunk then eventually a sad drunk. I wasn’t ever really an angry drunk. When I quit drinking, my pot consumption increased rapidly. Over time I noticed I was often feeling irritated and annoyed, sometimes rageful and pissed, the slightest things set me off and I react aggressively and communicate argumentative manner (sort of like extreme PMS, but all of the time). I took me a long time to realize that marijuana affects me this way because I believed the same thing you do, pot doesn’t make people angry or aggressive. But I’ve witnessed a sudden shift in my mood/attitude directly after smoking so many times that I cannot deny the connection. I don’t want it to be, but this IS all true. Pot does have the potential for negative effects. We all experience the world differently.

  • Mitch Bligh

    A squirt of CBD oil in the morning seems to do the trick!

  • Allie

    I get kinda cranky at times. It’s an unpleasant side effect of medicinal use for me.

  • Emilee Bauer

    Yes, do more research on the effects of weed on the brain. Its out there. This is a mind altering substance, no shit. Lol. Theres going to be negative effects for sure. Especially if you smoke every day. It has therapeutic and medicinal benefits that are extremely important for some people. Weed and all substances need to be respected, understood and used properly. I love weed, and it has caused me so many problems. Ive abused it and smoked it when it doesnt need to be smoked. Be aware. Do research. Everyone is biochemically different as well. Our experiences wont always line up. Enable yourself to see all sides and perspectives. Open yourself to facts instead of being biased based on ego. Im saying this because i come across countless defensive stoners that think weed is just this amazing harmless thing that is so natural and pure and couldnt possibly affect anyone negatively. They need to get their heads out of the smoke.

    • Brian C

      Weed and all substances need to be respected, understood and used properly.

      This is a great statement. So true. Its a lack of respect and responsible use that gets substances banned and regulated

  • Chad Brown

    For me it depends on existing mood and the strain. No one I know is in a good mood all the time. Some strains can cause strong emotions which can impact your social reactions. Outer space is great for pain but makes me quick to defend myself or take a comment in a negative manner, while alien duchess is also great for pain but allows me to stay level headed and not be so quick to judge.

  • Christopher

    I just started using Mary’s Medicinals 1:1 cream for chronic pain. I’m on a path of getting off opiates and it seemed so far so good. I’d cut my need for other pain meds in half. But I do find that I am getting quite agitated and can’t hold my tongue lately. I feel angry constantly. This is a detrimental side effect for me. I love what it does for pain, can still function, and am not as sleepy as I am with the other pain meds. Has anyone else ever had such issues with a synergy dose? Should I change my ratio? Newb looking for help.

  • Bigmoe99

    If someone is constantly badgering you or won’t stop pressuring you, agressive tendencies is normal regardless of if you’re on canabis or not.

  • Emily

    I have become quite grumpy when i am not on cannabis. I find that toking makes me happy, at any time and any day. but i am quick to become emotional (angry, sad) for impractical reasons. I deal with my mood by smoking, and instantly I am in a good mood and feel more “in-checked” with my feelings. But if something were to upset me while i am high, i will go off. If im not high, i find reasons to be pissed off at someone or something. Before my dependancy on weed I was known for being “chill”. Now i cant justify my emotions or feelings. I will definitely say that weed is doing more harm than benefit, but I can live with it. I am searching for better options for pleasure other than weed.

    • Marosia

      same shit

  • carolyn cavalier

    I have been using cannabis edibles for sleep for several years, and I seem to wake up anxious and a bit cranky every morning. Anyone else have that experience??

  • Kathleen Scott

    When my husband smoked weed and drank, he was emotionally unstable for sure. Then he quit drinking and smoking pot for a couple of years and mellowed out. Now he’s back to smoking pot almost daily, and he is definitely grumpy and lacks impulse control. I feel like my existence puts him into a bad mood. When I brought it up, he said, ‘Oh, that’s only with drinking.’ He can’t seem to make the correlation. My observation is pot alters his daily mood significantly, even without alcohol consumption.

    • Lee

      The reason I came across this article is because I’ve been suspecting my nightly puffs of cannabis were the cause of my daily grumpiness as of late. It’s gotten kinda bad and I’ve decided to take a break from it being a regular thing. You said, “I feel like my existence puts him into a bad mood.” It made me think about my wife, and how I have a feeling that she has been walking on egg shells around me for the last few days, because of my grumpy demeanor. The idea that she might feel like her existence puts me in a bad mood breaks my heart.

      Your comment touched a nerve, and thank you for sharing it. I wish you and your husband the best!

      • That was me and my wife as well. Everything she did annoyed me when I was smoking.

    • mamiel

      I get this effect from both cannibis and benzodiazapines. The day I take it I will be chill, happy, euphoric, but the next day I am way more likely to snap at people and lose my temper. I sense that taking CBD may mitigate the grumpy effect but I’m not totally sure, I’m still experimenting.

  • I’m struggling with this. I only started smoking week about three years ago at 47. At first I smoked about 1-2 times a week, but I noticed some irritability If I smoked much more than that. At some point I started smoking about four days a week for a while, and didn’t realize it was making me really short-tempered. I quit for a month, and the next time I smoked it, I was in a really crappy mood the whole next day.

    I’ve come to the conclusion that I just can’t smoke it. It’s a shame because my wife smokes daily and doesn’t seem to have the same problem, but I can’t smoke it with her.

  • Christopher

    As a followup on this, I’m wondering: is it personality or genetics? Nature or Nurture? Well, if you have had a DNA profile created for medication metabolism (my pain doctor had it done for me), could you share a) how many times a week you use cannabis b) your general results for the DNA test (mine was SLOW metabolizer), and c) whether it makes you cranky or irritable the next day or in general. Maybe we’ll figure something out here. Or not. Maybe it just puts your mouth on hold whilst using, then releases it later (like a snow plow pushing “grumpy”).

  • Allie


  • Thanks for the snarky response, but:

    1) It took me time to realize that weed make me an a-hole
    2) It don’t smoke it. The past tense used in the sentence (“when I WAS smoking”) indicates that I don’t smoke it any longer.

  • Arthur Visser

    It makes you grumpy the next day, this is well known and is because the effect weed has on various stages of sleep. Deep sleep is the 3rd phase of sleep where your brain ‘repairs’ itself. Rem sleep is the fourth and last stage of sleep before you wake up and is associated with dreaming, and the transferring of data from short- to long term memory. If you wake up from deep sleep you feel fuzzy and grumpy. If you wake up from rem sleep you feel awake and ready for a new day.
    Because weed lengthens the deep sleep phase and shortens/nullifies rem sleep, you wake up grumpy and irritated. This effect is gone after a sober night of sleep.

  • nik lazio

    Thank you for writing this article. I love marijuana and I need to break up with her. I am a long time pot smoker, a few years ago I began to notice/experience the exact personality changes reported in this study: changes in interpersonal behavior and experience, a pattern of interpersonal withdrawal, hostility, and diminished interpersonal skills, increased aggression. It took me a while to recognize and accept the connection between these mood/personality changes and marijuana.

    Have you ever met a grumpy pot head? Meet me.

    I’ve been smoking daily for about 12 years. In the beginning, I was smoking once or twice a day. I don’t recall marijuana making me feel irritable or hostile, usually quieter and sometimes a little paranoid. Shortly after my began my relationship with weed, alcohol joined the party and became my drug of choice. Over the next few years my daily consumption of marijuana slowly increased, while my alcohol consumption rapidly increased so severely that eventually I had to give it up. In the absence of drinking, I began smoking pot way more often. Believing that weed is harmless and had little to no negative side effects, I actually thought “thank goodness there is something I can consume (aka abuse) all of the time with no negative repercussions.” I started smoking in the mornings before work and noticed a severe attitude change. When usually I would enter work in pleasant mood and open to conversation, suddenly someone saying “good morning” would send me into an internal irritable furry, unable to fathom why this person is talking to me. At the time I blamed it all on alcohol withdrawal for these intense mood swings and personality change. Of course that would contribute to my changed emotional state. However after more and more experiences of witnessing my mood suddenly shift to feeling completely annoyed and mad without any obvious reason, I began to suspect a pattern. This shift often happened right after smoking weed.
    It’s taken me quite a while to realize and accept this connection. Getting high makes people chill and happy, not uptight and grumpy. A few more years down the line, I’m smoking many times daily (around 2-3 grams each day) and realizing I’m often neither chill or happy. My social interactions become especially upsetting, I snap easily over nothing and speak in a hostile tone, and feel just as surprised at my reaction as the people it’s directed at. What used to be a mood swing evolved into what I perceived to be my personality. Then I begin to question “When did this become normal? Why do I feel so annoyed and mad so often? Have I always been this way?” I start trying to remember my personality before marijuana and alcohol abuse. I’ve always been a bit anxious, socially awkward, experience depression, as well as energetic, social, very empathetic. But I don’t recall feeling so uptight and so reactive so often. Fast forward a year to present day, I’ve accepted that I am once again going to have to give up the main thing I use to live my life. I’m not sure how much of my current personality and emotional state have been influenced by marijuana. I understand that addiction is a symptom of negative states of mind, and that marijuana has the potential to amplify whatever state one may be in. But through many reflections of my past and current experience, I cannot deny that smoking marijuana affects my personality in negative ways. Now the only thing to do is quit. Unfortunately a long term high consumption user like myself will experience withdrawal symptoms for the first few weeks, which include feelings of anger, irritability, and/or aggressiveness, apathy, depression. Basically a lot of what I already feel without being high. It can take 2-3 months for your brain to reset to it’s natural state. I have started seeing a therapist to help me through this process./
    In some ways alcohol was easier to quit, it became so toxic in my body and challenging for me to function in my life I had to quit or I was going to end up eventually killing myself in one way or another. The destruction marijuana has caused in my life has been much less severe and much less obvious. High consumption of marijuana doesn’t cause nearly as much physical harm compared to alcohol and many other drugs, and the culture today doesn’t seem to be aware of the potential harm it may cause, specifically emotional harm. I’ve actually found it taboo to say “I need to quit smoking weed.” Most people look confused when I talk about it. Weed has a reputation for being harmless, exempt from being considered an addictive drug. I am only aware of it’s lesser known harmful effects because of my direct experience. If I had not consumed marijuana in high quantities for years, maybe my experience would be different. If I had realized the potential harmful effects, understood the potential for addiction, maybe I would have been more hesitant or cautious with my consumption rather than allow smoking weed to replace the alcohol addiction I had just quit.
    I cannot fully understand and appreciate the way weed affects my emotional state until I live without it. I can understand and appreciate that marijuana, along with all of it’s potential positive and beneficial effects, does have potential negative and harmful effects.