Gambling addicted man in front of online casino slot machine on laptop computer at night.

(© AA+W -

BOSTON — There’s a saying that “nothing good happens after midnight.” Now, researchers from Mass General Research Institute say there may be scientific evidence to back that claim up!

The team has created a new hypothesis that the human brain is not meant to be awake after midnight. Moreover, they say staying up late only leads to more impulsive behavior and high-risk decisions, such as drinking, overeating, gambling, or criminal activity.

Specifically, researchers suspect that staying awake during the biological circadian night (the middle of the night for most people) causes neurophysiological changes in the brain. This causes people to view the world more negatively than they do during the daytime.

“The basic idea is that from a high level, global, evolutionary standpoint, your internal biological circadian clock is tuned towards processes that promote sleep, not wakefulness, after midnight,” says senior author Dr. Elizabeth Klerman, an investigator in the Department of Neurology at Massachusetts General Hospital, in a media release.

Klerman is hoping their hypothesis will lead to further studies on how day-night differences in our circadian rhythms impact human behavior, decision-making, and job performance. The results could have important implications for countless people who have to stay awake in the middle of the night — including police officers, pilots, and health care workers. Study authors add that understanding how the brain changes after midnight could even lead to new strategies to combat crime, curb substance abuse, and prevent suicides.

“There are millions of people who are awake in the middle of the night, and there’s fairly good evidence that their brain is not functioning as well as it does during the day,” Klerman says. “My plea is for more research to look at that, because their health and safety, as well as that of others, is affected.”

The brain gets a bit risky after midnight

Previous studies have found that people are more likely to engage in harmful behaviors during the night. Statistically, incidents of suicide, drug use, and violent crime are all more common at night. At the same time, people are also more likely to make unhealthy food choices after dark, including chowing down on more processed foods, fats, and carbohydrates.

Study authors admit that some of this is explainable without looking at a person’s brain. It’s obviously easier to commit crimes or get away with unhealthy habits under the cover of darkness — when there are simply fewer people around to catch you.

However, the team notes that there’s also a biological cause as well. Klerman explains that our circadian rhythms change over the course of a 24-hour day. Simply put, people look at things one way during the day and in a completely different way at night.

Study authors add that positive affect — the tendency to view things in a positive light — is higher during the morning hours. This is also when a person’s circadian clock is tuned for wakefulness. On the other hand, positive affect is at its lowest levels during the night, when the circadian clock is preparing for sleep.

Meanwhile, levels of negative affect — viewing things in a negative or threatening light — rise to their highest point at night.

Your risk-reward decisions are out of whack at night

Additionally, the human body produces more dopamine at night, which is a hormone tied to reward and motivation in the brain. Study authors believe this can alter the likelihood that someone engages in risky behaviors when they stay awake after midnight.

Along with circadian-influenced changes impairing a person’s decision-making, night owls start to make poorer choices based on a “mental map” that is much more negative than it is during the day. Klerman says she experienced this while suffering from severe jet lag during a trip to Japan.

“While part of my brain knew that eventually I would fall asleep, while I was lying there and watching the clock go tick tick tick—I was beside myself,” she concludes.

“Then I thought, ‘What if I was a drug addict? I would be out trying to get drugs right now.’ Later I realized that this may be relevant also if it’s suicide tendencies, or substance abuse or other impulse disorders, gambling, other addictive behaviors.”

The hypothesis is published in the journal Frontiers in Network Psychology.

About Chris Melore

Chris Melore has been a writer, researcher, editor, and producer in the New York-area since 2006. He won a local Emmy award for his work in sports television in 2011.

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  1. Tom Dockery says:

    The reason that violent crime occurs more frequently at night is that you can’t see them.

    1. EarlyBird says:

      This is the most comical piece of the article:

      “Klerman says she experienced this while suffering from severe jet lag during a trip to Japan.

      ‘While part of my brain knew that eventually I would fall asleep, while I was lying there and watching the clock go tick tick tick—I was beside myself,’ she concludes.

      Then I thought, ‘What if I was a drug addict? I would be out trying to get drugs right now.’ Later I realized that this may be relevant also if it’s suicide tendencies, or substance abuse or other impulse disorders, gambling, other addictive behaviors.”

      So one of the authors of the study couldn’t sleep one night from jetlag and some how thinks to herself “what if I was a drug addict? I would be out trying to get drugs right now.” How does that make any sense at all? If you were a drug addiction you’d be out trying to get drugs everytime you didn’t have them. Because it was late and you couldn’t sleep that means drug addicts are trying to get drugs at night? This is complete nonsense. This is the dumbest premise for a study I have ever seen.

  2. Stark says:

    How much did this study cost? And who funded it?

  3. Michael Bol says:

    Total rubbish your brain is tired at midnight if you are not used to it and you act differently, like being drunk does. If you work midnights then it’ll be the same as a day worker, only darker outside. I hope my taxes did not go to this study.

  4. Bob says:

    No mention of the fact that there is no universal circadian rhythm? The world telling me I must sleep early and go to work early made my life miserable. Now I wake up around 11 PM and work from midnight to 8 AM. Never had a schedule I liked more.

    1. Ted says:

      But posted at 430pm…?
      You LIE

  5. Crotte says:

    Total rubbish I have stayed awake 2 days or more due to work I had to do. What bunch of moronic idiots are paying to have this crap published that includes the moron writer of the article.

  6. Solarkat says:

    Wow, you negative commenter night owls are proving the study is probably correct. More research is surely needed!

    1. luke2236 says:

      …and you must be getting something off these bogus ‘studies’. eeoc employee or living off of taxpayer funded ‘grants’ , huh?
      The ‘study’ is krap.
      Not everyone is wired the same and yes more crime happens after midnight because its dark, places are less populated than earlier and many if not most people are asleep. period.

  7. Steve says:

    Obvious that the people that wrote the comments stay up too late on a regular basis. I think if someone from the study was with them, they would rob and beat them and maybe drink their blood, proving their findings are accurate.

  8. Brad Smith says:

    Wow, what a Gish Gallop, they threw everything but the kitchen sink in didn’t they? LOL

    That’s usually not a good sign. If they had anything that was actually relevant they could have led with it and proven their point right away. Instead they lead with the idea that suicides do mostly happen during the day, But, well sometimes they happen at night and if you torture the math enough you can make it look otherwise. Yeah, well who actually accepts this type of data manipulation? Nobody in the scientific community would just accept this changing of the data without some better reason than they gave. If your brain is all screwed up at night and this makes you crazy then what’s making the people crazy during the middle of the day? LOL They don’t even try to say.

    The rest of these data points at least the ones that are even remotely valid actually deal with Sleep Deprivation, which Does NOT prove anything about the brain being out of wack during the night. You can work nights and sleep like a baby. And correlation vs causation is all messed up here. Are people who are having financial or marital issues not sleeping well because they stay up too late or are they staying up too late because they are having problems they can’t deal with?

    I’ll buy it that people who aren’t sleeping well will have all kinds of problems, and people with all kinds of problems often don’t sleep well, which came first? Who knows, but nothing in this study convinces me that simply being awake later at night is causing any problems. The absolute worst part of this “study” was torturing the numbers on when suicide is most likely to happen. The obvious reason for some people, mostly single men to kill themselves at night is they wait until night because they are off of work and have had time to work up to it. For women, the daytime is often the easiest because the kids are at school and the Husband is at work (if they have one) and lot’s of people kill themselves during the lunch hour who have jobs, but again this is because they have time to be away from people. Suicide is generally speaking a solitary endeavor, that alone explains the timing and they did Nothing to address even this simple fact.

  9. BH says:

    I was a working musician and songwriter for many years. I, and many in my field, find nighttime more conducive to creativity. Many recording sessions went late into the night and we’d stop at a diner or the like for breakfast before going home. I’m retired now, but I’m still a nightowl, going to sleep btwn 4 and 7 AM. My brain is just wired like that.

  10. Joseph J. Menkevich says:

    Whoever wrote this article is a complete idiot.

    Strong Coffee & Chocolate Verify: Brain is Happy.

    Feed the brain after midnight.

  11. edward says:

    Another stupid study by someone wanting to get “published”. I’m over 80. Bed time is between 1 am -3 am. Didn’t realize my sleeping habits were unhealthy. I should be thankful I’m still alive. The next thing some study will tell me nicotine, caffeine and grease are bad for you. Exercising less and eating more is probably not good for ones longevity either.

  12. Tina Marian says:

    This is bullshit. What about night workers? I worked nights as a nurse for years. My son works nights. I am a writer, and I often do my best work after midnight. What a waste this article is!!

  13. Greg Bacon says:

    Sounds custom-made for the Deep State. Claim criminal activity goes up after midnight, then ban any gatherings so those pesky peasants won’t plot & plan to overthrow the tyrants.

  14. E.D.F. says:

    I call B.S. on this. I worked midnight shift for more than 15 years. No accidents to or from work, thru all kinds of weather and even a blizzard or two. I worked as a production machinist working to aircraft tolerances and produced good product all the time. No lost time due to work related injuries. I was one of several hundred employees at the time.

  15. Megiddo says:

    That article is absolute comedy gold.

  16. David Allen says:

    I did a study at my place of work in the eighties when working the midnight shift for ten years. Using divergent thinking as the measure there was a significant difference at p=.05 between the midnight shift and the day shift. There also was a significant difference between the midnight shift and the afternoon shift. These differences showed the midnight shift performed worse than the other two. Interesting the swing shift was not significantly different to any other shift.


    I now work a 12 hour shift, starting at 04:00 AM. Been at it for 4 years now after working day shift for 30 years with a three year swing shift in there somewhere.

    The 12 hour shift is the worst I have ever worked. It is very difficult to exercise, read books, enjoy vacations, etc. However, the beer tastes better!

    We need more comprehensive studies, using shift working adults in the work place as subjects, rather than the 20% or so people who could have other issues that may add too many variables to results, causing misleading study findings.