Life Science

Does a full moon actually affect people’s behavior?

- Asks Sue from Long Island, N.Y.

March 31, 2008
Is the moon making us crazy? [Credit: <a href="">Stelios Kiousis</a>.]
Is the moon making us crazy? [Credit: Stelios Kiousis.]

I admit that New Yorkers are not known for their superior driving ability, but on this one night the drivers seemed especially erratic. People kept cutting me off. One guy sped right through a red light, barely missing a collision with the crossing traffic. And some genius, perhaps British but probably not, forgot that in this country we drive on the right side of the road.

I thought about what made this night particularly favorable for lunatic drivers compared to any other. It wasn’t St. Patrick’s Day, New Year’s or very late at night, so drunk driving didn’t seem to fit. Only when I got out of my car and looked up did I conceive a possible explanation: the full moon.

The legend of the full moon’s effects on human behavior has existed for centuries, popularized by the myth of the werewolf. The words “lunacy” and “lunatic” are derived from the same Latin root that gives us the word “lunar,” as people often attributed intermittent insanity to the phases of the moon. While many people believe the full moon influences behavior, scientific studies have found very little evidence supporting the “Lunar Effect.”

In 1978, University of Miami psychologist Arnold Lieber wrote the book The Lunar Effect: Biological Tides and Human Emotions. He argued that the moon influences day-to-day behavior and concluded that homicides increased during the full moon after analyzing Miami’s crime records. Similar crime studies during that same time period, however, found no such relationship.

Then, in 1986, researchers from the University of Saskatchewan in Canada combined the results of about 100 studies and found “no causal relationship between lunar phenomena and human behavior.” They discovered statistical flaws in many of the papers that claimed to find such a link. They even reanalyzed Lieber’s homicide data and found no correlation.

More recently, numerous studies have been conducted by intrigued researchers, with most attempts to blame the moon for everything from suicides to vomiting after surgery coming up empty.

So with all this evidence to the contrary, what makes the full moon lunacy theory still so popular? Perhaps it’s the media, who know people are more likely to read a crime story if some police officer blames it on the moon. Or maybe people just want to hold onto an urban legend that’s been around for hundreds of years.

A more scientific answer may be selective memory. If some bizarre murder or car accident occurs, people are probably more likely to remember it if it happened during the night of a full moon.

After reading up on some studies — including one from the authority on this topic, the University of Saskatchewan — I’ve decided that the full moon was not responsible for my experience on the road that night. Perhaps I selectively forgot the thousands of other times I encountered lunatic motorists. Though I have no scientific evidence to prove it (just years of experience), I’m going with the theory that New Yorkers are just really bad drivers.

About the Author



Dr.Philip says:

Ive have believed this for quite a long time, for some researchers have done numerous studies on the subject, I too have had side effects in the mood swings are rapid when the full moon is out. To think that a moons effect can actually change how you act sounds crazy but if the moon can make the sea rise because the gravitational pull then i to believe that moods can change as well.

So to the people that do not believe…id say don’t be naive to the biggest discover scientist cannot prove.

For you cannot see air though you know you can breathe.

Cauly says:

It’s called confirmation bias. A good point!
I believe the full moon effect is the same as animals have. The full moon illuminates the sky and all predators take advantage of this. Why should we believe we are any different?

joe figaro says:

Wow, there are a LOT of crazy people commenting here! I bet you all love those ghost hunting shows too!

debbie says:

I have a 21 yr old son that is fine until we have a full moon, he wants to hit things and get mean when the moon is full what can I do about this???? The rest of the time he is fine.

William Soisson says:

I live in tropical Africa, and every full my wife goes ‘loony’ with agitated anger. Seems the closer to the equator, the stronger the influence? I’ve seen it in other people here, too.

Kevin Lawson says:

The closer the moon gets to the earth during its 28-day cycle, the more full it becomes and the stronger its gravity. As the moon swells in the night sky, its gravity causes high tides, both in the ocean and within our human bodies, which are mostly water. The effect of this internal tide reaches a tipping point for some people (particularly the unchaste and immoderate) just when the moon becomes completely full. The “humors,” or moderating fluids within our bodies, are contained in vessels that are gyroscopically controlled so as to remain in alignment with the earth, however, when the internal tide is high, those fluids spill over, triggering bizarre, ungodly behavior.

To ensure that this displacement of our emotion-regulating fluids would not happen, God originally placed the moon further from the earth, but the accumulating burden of man’s sin has increased the weight and gravity of the earth, continuously pulling the moon closer. The full moon effect some are noticing now will become ever more prevalent as we approach end times. So each time that lesser light of the heavens reaches its maximum brilliance, lock your doors and guard your daughters. If you suffer from full moon effects yourself, perhaps it will be best if you are on the outside of that locked door. Devote yourself to prayer and try to remain in the shadows.

Ciara says:

I normally am a great sleeper but once a month I don’t sleep at all and it’s always on a full moon. I do believe it has an effect on me personally.

sherry says:

I worked at a mental hospital for three years. Trust me, we employees knew when it was a full moon. The moods and demeanors of the patients changed very noticeably and sometimes drastically.

EmeraldFire says:

Hi, my name is Emerrald. I’m really quite embarrassed to say this. I’m someone who is very down to earth and I don’t put much thought in to legends or ghost stories unless I have had an experience. I am a very truthful person, almost to the point it being painful. Anyway since I was the age of twelve I’ve notice that there were some nights where I couldn’t remember anything. My grandmother would always either sleep in the same room as me, or if I was sleeping alone she would always make sure my door was closed and that she was always near. I would always think this was strange. I’m a blind person so I would not be able to tell if it would be a full moon or not. But before these stranged instances where I would be unable to remember I always felt my sexual drive increase almost to the point of it being painful. I always felt strange and nervous because at that time I had no idea what was happening to me. It frightened me. I would always ask my Grandmother what was happening, and she always told me to never bother about it because she would protect me. It was till later that when ever my sexual drive would increase that it was close to the full moon, and that the nights where I lost all my memories on what happened the previous nights would be a full moon. When I first heard this, it made me laugh. Because I thought it was just something that my grandmother was telling me to scare me. She said that I would become so sexually aroused that she had to keep an eye on me. She told me that it was almost like seeing someone in heat. I finally realized that she wasn’t joking. I want to know if this has ever happened to anyone else. I want to know why I can’t remember anything. I know this sounds weird, but it happens to me, and it scares me. Because I’m truly vulnerable when this happened. This is not humanly possible, so why is it happening to me.

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Rupert says:

Over the years I have become increasingly aware that in the lead up to a full moon I am.restless anxious and moody. The effects timing is now more than coincidence. The moment the moon is full, literally the moment I am.back to normal.

I guess I’m just searching for others. I’ve spoke to loads of guys who experience similar, there must be an.explanation?

Courtney says:

I don’t care if there is proof or not, I believe it has an effect on people. My boyfriend is like clock work the week leading up to a full moon. He becomes extremely emotional, irritable and overall unpleasant to be around. It’s like a different person. I shit you not I can sense it coming and it’s always before I find out the moon is actually full so it’s not just some mental trick I’m convincing myself of. Its like clockwork. The closer it gets to being full the worse he gets. Then just snaps out of it. Add in the fact that everyone at work is also seemingly angry and argumentative and ive got enough proof to believe something goes on. Not with everyone. But some.

Not you says:

My mother and I have trouble sleeping during full moon. Do I feel homocidal?… Hmm, I would say yes. But it is my usual state, so I can’t tell if the moon affects it. Although it should. If it can affect huge amounts of water it should also be able to make changes in tiny human beings. SCIENCE.

Someone says:

Full moon tonight, and guess what… I am super restless and anxious for no apparent reason, well I do have PMS.. I hate working during full moons, work can seem extra stressful. I’ve noticed the moons effects on me for many years.
Great reading all of these posts. Looks like am definitely not the only one..

Allan says:

Presently, this is mostly a cultural phenomenon left over from the time before ubiquitous electric light. When the moon is full, there is light to see at night; as such, people used to be able to go out and interact with each a lot more during this time of the month. As a result, of course stories of this or that happening during full moons were frequent. It’s not that the tides can possibly have some sort of mystical affect on people, affecting their brain chemistry, it’s simply that you can see more when there is light to see by.

Full moons used to (not even that long ago) have a more dramatic and significant impact on society, but now it’s mostly just people with poor critical thinking skills, desperately wanting to associate the motion of the planets with our personalities. Believing that the moon/tides directly affects people is exactly the same as believing in astrology; and if you believe in astrology, well, that’s the end of that argument right there.

Hayley says:

To start off love reading the Barber mans story!!! I walked into work thismorning and said to my friend “I swear my other half suffers from a male version of PMT or that we just had a full moon” I sat at my desk logging in and thought the last time he bacame all strange and argumentative was on a full moon. I looked up when the next full moon was and low and behold it was 5.56am Wednesday. Last night was Tuesday so Full Moon. I stronlgy belive in this. It for sure affects people on a small or large scale. I always made a joke and said to him he gets PMT but i now belive its the Moon. My research brought me to this site.

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I have worked with the elderly [people with dementia]Doesn’t surprise me , for years, there is a different and very marked behaviour change in them when there is a full moon.One lady would keep asking me when the bus was leaving for Auckland and was it late…..only when it was a full moon. I also have a very good friend who is in denial about her mental state, who becomes quite radical and tends to start dwelling obsessively, about her past…only on a full moon. Lots of other examples. For some reason it affects people who are unstable.Doesnt surprise me that horror movies often feature a full moon , there must be something in it.

To Emerald Fire, read your post and it seems very odd, how old are you I wonder, Sexual desire can occur at a certain time of the month, and yours just might fall when there is a full moon, it is natural for females to have strong sexual urges at a certain time of their monthly cycles, I would be worried about my grandmother if I were you.By the way ,how did you manage to write this if you are blind?

joseph ravert says:

during the full moon I always have trouble thinking but why does it affect our behavior

joseph ravert says:

and the way we act

Josh says:

I’m pretty sure there is enough scientific data to conclude this is nothing more than an urban legend. Studies show that the moon phases have close to no influence on human behavior. In fact, research shows that there is more cranial force placed on your head from just simply laying on your pillow to sleep, than the tidal/gravitational pulls/forces. I am an elementary teacher and wish there was an explanation for some of these kids crazy behaviors!

imnopatzer says:

When the moon is full or nearing the full moon phase, my 9 year old son consistently becomes super pleasant, very cooperative and extremely obedient and helpful. But the next weekend after the full moon is over, he can be a struggle.

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Andreanna sander says:

I was just thinking, if this lunar effect is just a myth, then why don’t I remember anything that happens on the night of a full moon. You know when I was eleven I used to think I was a werewolf but I did’nt think of the common science in it. I personaly think that the lunar effect is real. I was doing scienctific reasearch on this exact subject and there many cases that prove this theory is NOT A FAKE. I also personally think that this information was not at all helpful in my cotinuium of research. Thank you. Sorry if this hurt your feelings.

Your helpful freind,
Andreanna Sander

srizee says:

for the last 35 years i have been observed that I got anxious, quarrel some, any tense situation creates automatically without any prejudice thinking. It begins before 3 days of full or no moon & one day after both. this is totally beyond control, unavoidable. I am not able to understand handle the situation which arises all of sudden. What is connection of it.scientifically or astrologically.

Nicole says:

I’m a person who believes things when I see them. I’ve always been on the side of Science, and I’m known to critically over-analyze. That said, I have come to believe that a connection may exist with human emotion and lunar cycles, because I’ve experienced it myself. I’ve never kept track of lunar cycles, or even paid attention to lunar phases on calendars; it was never important to me. one day/night, a couple of years ago, I found myself to be in a terrible emotional state: highly moody and irritable, restless, angry, anxious… and I couldn’t sleep at night. I found out after the experience that it had been a full moon. I’d not have thought much of it if it weren’t the case that I’ve continued to have this experience again and again: I’ll have a sudden experience of intense and painful emotions, and discover afterward that it had been a full moon that night. The knowledge of the full moon always comes after the episode, and never before, as I don’t track lunar cycles, and I never anticipate full moons. Could it be possible that, somewhere, deep in my subconscious, I’m noticing and storing information about lunar cycles, and I am unknowingly psychologically reacting to a subconscious false-belief? I can’t say it’s impossible, but I can honestly say that I don’t know when full moons are coming: I don’t check the calendar,.. I don’t look them up online. How can it be that I continue to experience this strange coincidence over and over again? It certainly opens me up to the possibility that there could be some correlations here. Because I’m noticing a trend in my behaviour that I can’t explain in any other way. I’d love to say it was my menstrual cycle, though the mood swings aren’t matching up with my ovulation or pre-menstrual cycles. In fact, most recently, the emotional episode I experienced on this most-recent full moon was during a time when my menstrual cycle when I am predictably my most pleasant. I’d really like to get to the bottom of it all, so that I could turn my focus to mood management, for my own emotional/mental health, and for those of the people around me! :)

– N

Lyn says:

Last night, I went into my room and saw it brightly lit by the moonlight of a full moon. I got so happy and rushed to my window and looked out.

I saw so much blue in the sky and in the neighbourhood. I felt so happy and calm. My heart literally felt like melting and I was crying tears of joy …?

Naomi says:

My father his mother, and his grandmother and great grandmother and great great grandmother and I all have been finely tuned emotionally to the moon. The week leading up to the full moon our emotional stability wavers, if we’re having a great week little things affect us more than they would any other day of the month, without looking at the calendar we have all known when the moon will be full so I can personally attest that people are in fact connected in some way to the phases of the moon and those people who think it’s bullshit are disconnected from everything. Everything that makes life worthwhile and I’m not talking about friends or family I’m talkin about where we came from, the hunters and the gatherers. I know that I’m sixteen and that many people may not think that I have the right to say stuff like this, that I don’t have enough experience but I am born no ordinary sixteen year old. Almost every person I’ve ever met has said that I have the wisdom and maturity of someone far beyond my years. you can think to yourself that I’m just an emotional sixteen year old girl and that nothing I say has any creedence. But to that I say go to hell I can probably knock you off your feet in a real conversation. The moon does have an effect on people. So put down your busy lives and listen to te world around you. The nature. The energy.

My class never acts different on a full moons night

I like these facts

narada says:

I think full moon has a effect…My wife try to fight (aggressive) with me on full moon days (or couple of days before/after the full moon). that is my personal experience…

Adam beech says:

Try sitting in an AA MEETING for about 60 days. You can set your watch to a full moon . All of us seem to struggle with things that we ordinarily handle with ease. There are those who become irritable , restless and discontent for really no good reason. After 23 years of attending on a DAILY basis my research shows with out question that moon has a pronounced affect on some peoples emotional states.

Tony says:

My wife always fights with me on the Full moon or on the no Dark Moon, I have been going through this from past 3 years, we have been married over 10 years now..

matthew says:

the moon and sun and other planets effect everyone no one is immune to it. when the moon is in your zodiac sigh (house)and its full may god help you lol.

Nunya Biddle says:

If one believes, no one person, or any study will change that belief. With that said, I’m a victim of this belief. –
I am a switchboard operator and it always appears that I get more angry people, more odd and strange requests, more people with no boundaries and hide behind the anonymity of the phone during the waxing and waning of the full moon than any other time of the month. –
And whether I am actually cognizant of this fact in advance or not, I realize I’ve come to expect and associate certain behaviors to the full moon. Thus making them seem to stand out the most during this time frame. –
This being said I’ve simply come to the conclusion that I’ve always dealt with all this stuff every day but the full moon makes it “special” and my mind goes along with it.

tamia says:

I believe there is a possibilty of the moon having an effect on people. I for one do. But what I noticed one night was that me and my friend have two exes. And I couldn’t help but notice how their behaviors were from totally friendzoned to flirtatious… It wasn’t normal. We both explained to each other what happened. I don’t know if there is an absolute correlation to people and the moon but guys in my opinon do have changes in behavior. I have no severe evidence but Iwill be sure to keep a closer observation to past rrelationships.. Of course I won’t alter the results by making them talk to me. But it’s an experiment for now.

Charlene says:

I completely agree the full moon effects u ive worked at a nursing home for 5 years and when theres a full moon during that day and usually before and after the residents start getting agitated and confused and more so with a mental health problem ex. Anxiety depression etc.. And i noticed i myself would feel the same way that is until today ive sat back and watched everyone around me go crazy from residents at work to my husband who has bipolar my cousin who has bi polar and her friend as well lol they all were agitated , or emotional, confused and just plain off and my dog was even acting funny while walking him late at night tonight during the blue moon (7/31/15) he just freaked out and also on my drive home people were driving erratically now what are the chances of this all in one day! And tell me theres no connection! When nothing this exciting ever happens lol

Very good post. I’m experiencing many of these issues as well..

Susan says:

For a few nights I’ve not been able to sleep. Not fall asleep. Not stay asleep. Yesterday at work I was foggy and lacked confidence – just did not feel myself. My husband and I had an argument two nights ago – and we never do that! Today I had lunch with my BFF and she told me she watched a girl stop at a red light … and after a time – the person went through the red light – my friend was so angry she followed her and yelled at her! She also said that for the past few days she has been in a complete fog! My friend was shocked at her own behaviour having chased the driver. I just found out that we have been in a full moon. I have noticed this for a very long long time. Not every moon has such a great effect – This month is a dandy! Also working with the public most of my life, no one could ever convince me that the moon does NOT affect some people significantly.

LadyD says:


Edbel says:

In going to go with you and say that newyorkers are realy bad drivers but i useually find people just act wacky because they want to and just because its a legend so ✌

Anna says:

I am amazed how many stories there are on here. I think there have been studies that have looked for obvious correlations (like crime rates), but not many have studied more subtle effects, like mood and quality of sleep. I’m not sure we could ever get completely unbiased research in regards to this since the moon is both predictable and unchangeable.
I have also noticed a lot of people who have jobs where they interact with a lot of people (i.e. teachers, nurses, sales, etc.) and they always seem to say the same thing. I did not believe in the effects of the full moon until I became a teacher. Even then it was a joke at first. The students would have a very strange week of behavior (lots of energy and disruptions) and I just kept noticing that it always happened to be around the full moon.
Now I plan for it. I try to talk less and allow more time for movement and activity. I also try to be more patient, but since I’m effected by the moon as well, that doesn’t always happen.
I think it is similar to how some people are more sensitive to atmospheric pressure. It gives them headaches and body aches, and because they are achy they are more irritable. That is a real thing. Why wouldn’t the moon be similar?
I am still looking for ways people have tried to counter act the effects of the moon cycle. More Zanex maybe? Less caffeine and sugar? More exercise? No idea.

Sloatch says:

Then Guys !
Since everyone is denying our being emotionally unbalanced and want to discover away from the boring routine …Lets make full moon an international day of madness :D

jen says:

My personal experience is that I did indeed feel different during a full moon I always knew when it was full I would feel strange at work (strange not crazy )..I would tellmy co workers ” I bet you its a full moon ..I was always right ..

Cara Chapman says:

I have paid very close attention to the affects of the full and new moon on people. I worked for quite a few years in a hospital for the mentally ill and I have a bipolar daughter. I have done my own studies. I know the body is made up of mostly water and we need our sodium to survive with that being said I also know the moon affects the sea, salt water, therefore can affect any type of salt water. I, in my own studies, have found that not everyone is affected. The one’s I have seen affected the most are the Patients I had that were bipolar, schizophrenic, borderline personality disorder, pretty much the ones with the worst disorders and the higher level of their disorder. I found that while the full moon does affect them and they tend to get testy and can be quite mean and agetated easily, the new moon actually made them worse. The new moon, I’ve noticed with my daughter and with many of my Patients, made them not just testy but agetated to the point of violent behavior. We also had more admittions to the hospital on the new moon. I have never, that I recall, been affected by the moon although I suffer from severe depressive disorder. It seems to make those that get angry quickly more aggressive. This is my own personal study and my own opinion. I am not a scientist nor a Doctor, I am a certified medical assistant therefore not having much training, just evaluating.

Nhlanhla says:

The full moon is a time of positive opportunity if you use it correctly. It can increase your positive energy or conversely, it can wreak havoc on your emotions.
Since the full moon pours down a tremendous amount of energy, you must be in a calm state of mind to receive a positive effect. Remember that whatever is going on in your body, mind and spirit will be amplified.
If you are angry, you will feel angrier or if you are happy, you will feel happier. During the full moon, the ocean swells and emergency rooms have more patients. The energy is very powerful so it’s important to direct it with positive intention.
Crazy energy as well as loving energy will be intensified. Knowing this is a huge opportunity for your emotional and spiritual growth.

Maxine Lowe says:

I’m 64 now but I remember my mum showing dad’s diary
He died at 32 when I was 9 on every full moon
He wrote lost

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