Stuff You Should Know - The SAD Episode

Episode Date: January 8, 2026

Seasonal affective disorder, or SAD, is much more than the winter blues. It's a serious subset of depression. Learn all about it and what to do if you suffer from it today. See omnystudio.com/listener for privacy information.

This is an I-Heart podcast. Guaranteed Human. Welcome to Stuff You Should Know, a production of IHeart Radio. Hey, and welcome to the podcast. I'm Josh, and there's Chuck and Jerry's here, too, and it's a Stuff You Should Know ho-down to start the new year. Chuck's still wearing his novelty 2026 glasses that he got. Sponsored by Nivia, that I believe what you're saying was Ryan Seacrest himself handed them to you while you were at Times Square, right?

No, not handed. He put them on my face with his hands. Whoa. Is it because you guys are co-workers? Yeah, he's with eye-hard, didn't he? Yeah, but I think like half of the U.S. is a coworker if he's got so many jobs. Yeah, you're probably right. Well, if you haven't guessed listening audience, this is our first recording of the new year. Yes. I'm probably going to be a little rusty. Ear, e'er.

And can I just give a quick shout out to a couple of things? Yeah, please, too. Great. Well, Josh knows all this stuff because we communicate outside of work, believe it or not, because we're friends. But I went to New York City. Emily and I do our little Broadway weekend in New York over Christmas every year. And this year, I just want to say thanks to a couple of people, most notably, Natasha Hodgson of Operation Mincemeat fame

because she is in the show and put together the show and stuff you should know and she's been in magazines as people alerted us as giving stuff you should know credit as our episode inspiring that show and was kind enough to give us a couple of tickets

to go see it and it was fantastic. I highly recommend it. I know. I was loath to miss it. That sucked. I wish you could have been there but it's still playing. So maybe you can check it out. Yeah. I was especially upset when you said that she gave you.

She came out into the audience in the middle of the show and gave you like a bouquet of roses. No, no, no. And the audience lifted you up on their shoulders. No, that was, that didn't happen. Also, went to Bar Centrally, as I like to do before Broadway. What is that? Bar Centrali is where I go before Broadway shows. Well, what is it?

It's a bar, but it's sort of a. I mean, you can just make reservations a week out. I think I've mentioned this before. It's sort of a secret place in that it doesn't have a sign or it's not widely publicized. But, you know, seven days out from when you want to go, you can call them up. They specialize in getting people in and out of there pre and post Broadway. And, you know, sometimes you can see Broadway performers there on the down low. Nice.

I would have no idea that one could be sitting next to me and I wouldn't even know. Well, you might if it's a famous. You know, like Brian Cranston was sitting there. He was? No, but he could be. I saw, years ago, I saw Dexter in there. What's his name? Dexter's good enough.

Yeah, this year I saw the lady from Lost, although I don't think she's on Broadway. She was in there. But all this to say, big thanks to Jason, who helps take care of Barsentrali and Joe's on Broadway. He came over on his night off just to say hi and was just a total sweetheart of a guy. What a trip.

And then finally, I want to thank Santa, Santa Claus in the Radio City Music Hall show. I surprised Emily by going to the Christmas show this year for the first time. Yeah, I remember Santa wrote in. Santa wrote in. And although he was not in the performance we went to, Santa, Adam, was very kind to send a Christmas video to Ruby. Have you been to the show? No. I'm just some bumpkin who stays at home all the time, apparently.

Dude, you and you have to go to the Radio City music or Christmas Spectacular. It is one of the delights of my life. The Rockettes was one of the most impressive, most amazing live shows of any kind of ever seen. They were incredible. Wow. Okay. I'll go. Yeah.

And it's, you know, you guys love your Christmas cheer. And it really, you can't, even the biggest grinchy curmudgeon wouldn't help but get in the mood, even at the 10 a.m. show. But the Rockettes were amazing and Santa said that he turned them on to our listener mail and the Rockettes episode and some of the now current Rockettes are listening. Oh, cool. So a shout out to you, Rockets. Keep on kicking. Hello, Rockettes. We did a whole show on the Rockettes, didn't we? We did. Yeah. All right. That was amazing, Chuck. You were sick over the holidays and it felt terrible. Yeah, it really stunk. I got this cold that apparently there's like a two, week cold going around. Oh, no, that long. And it was just like every day I would add a new

symptom. And it was, I could do stuff during the day, but I was just sick the whole time. I'm so sorry. It was rough, yeah. So thanks for that. I appreciate it. But we still had a great Christmas. Well, that's good. Momo knows how to open presents. So she opened presents on Christmas morning. She was so happy. Pause or teeth? It was quite a both. Okay. Yeah, she's a pro. She knows what she's doing. She got some new rabbit treats. So she laid on on her back and rolled on those. And she had a great Christmas morning. That's wonderful. It was a good Christmas after all.

We hung out with friends on Christmas Eve and our friends, Laurel and Braden, and their kids, Elliot and Bear. I know those guys, right? Yeah, you do. You've met them plenty of times. So we got to hang out with little kids on Christmas Eve, and, man, that will put you in the Christmas spirit when you don't have kids of your own. Yeah. How old are those kids?

They're like eight and six, I think. Oh, yeah. That's fun. Prime age. Yeah, right in the zone. Yeah. So thank you, though, for your sympathy over my sicknesses. Yeah, I felt bad.

One thing I don't have, Chuck, which I am really happy I don't have, because it's awful, is sad. No sad's for you? I don't have sad. Do you have sad? No, I don't have sad. You know, we're talking about seasonal, effective disorder, and just right off the bat, we should point out, because I was about to say, occasionally I get the winter blues. This is not that. This is a real, it's legitimate depression and comorbid with stuff like bipolar disorder, and we're going to talk all about it, but it's not just, you know, I get a little blue in the winter sometimes when it's, you know, gloomy.

No, but it's tied to that. Yes. It's just, it seems to be an extreme version of that. But you're right, it's not, it's nothing light. It's classified, I believe in the DSM as a major depressive disorder. Yeah. with a seasonal pattern. I think that's the clinical name

for seasonal affective disorder. And there are people out there, I think something like 5% of people, I believe that's an American statistic. Yeah, that's America. Get the like real deal seasonal effective disorder where they have major depressive symptoms during the winter months.

But something like 10% are maybe even higher than that in the United States. States, people get what's called sub-syndromal seasonal effect of this order. So where you don't have it where it can be considered major depression, but it's definitely worse than the holiday blues. And the weird thing about this, although it's not so weird once we explain it, it is seasonal. It's tied to winter. And it seems that they figure, or summer, which I, that one's just mind-blowing to me. Yeah, we'll get into that. Yeah. It seems like they have it

figured out. They have this, they have it explained. So this is one of my favorite episodes where it's like, here's how the human body works. Here's what's messed up with this when we're talking about this. Tadda. I love episodes like that. Yeah, not a lot of mystery. Big thanks to Livia for getting the new year off to a great start with another banger. Yeah, here, here. Yeah, we should say that this is something that hasn't been officially, I mean, it's obviously been around since, you know, time began because, as we'll see, it's tied to seasons and especially light and how much light you're getting. So that's always been a thing. But it hasn't been officially diagnosed as a thing for that long. It was in 1984 when there was a paper by researchers at the National Institutes of

Health, the particularly guy named Norman Rosenthal, got together and they discussed these almost 30. I have a feeling one dropped out because there were 29 patients. Most of them had bipolar disorder and they all had what we now know is as sad. Yeah, that 30th one, when they, like, one weekend, they're like, how do you feel? And they were like, fine. And they're like, you're cut. You can go out of here. Yeah. So yeah, bipolar disorders will see, like, really kind of ties into this. It seems to be, like, also seasonal in some weird way, too. But pretty quickly after that 1984 paper, the DSM went all in. Three years later, the DSM 3R, as we all know,

R stands for revised or rocking. That came out in 1987, and it was, like, now it was a diagnosis, but it was used as a modifier, as we saw, major depressive disorder with a seasonal pattern. So it wasn't its own thing. It was just a subtype, essentially, of an existing depressive disorder. That's kind of how they first had it.

Yeah, and, you know, because it's seasonal, the most common kind of sad that we think about, and like we mentioned, it is very serious thing, and it starts off in the fall, maybe early winter, and it kind of depends on where you are, as we'll see, although not always intuitively, there's a third act reveal that might surprise some people. It generally subsides in the spring, but I did mention that odd spring and summer variety. That hasn't been studied much. it's very, very limited, about 0.5% of the population has this opposite pattern, but it is a diagnosable mood disruption.

It just happens in the spring and summer, and it's tied more to sort of like oppressive heat and maybe unsurprisingly, some of the things they recommend for that, which, again, we're going to cover a little more later, is stuff like maybe stay inside, dim the lights, that kind of thing. Yeah, and the thing that gets me about the summer version that much rare one, is that the symptoms are almost, in some cases, opposite the symptoms of winter. So usually when you first start getting sad, it's around young adulthood, ages 18 to 30, I think. And most people who get it get it most years, but you don't necessarily have it every year.

Women are four times likelier than men to have it. And if you have an existing mood disorder, you're much likely to suffer from season. effective disorder because it's almost like it takes your existing mood disorder say bipolar two and just builds on it there's an extra like environmental punch to it that really kind of kicks it into high gear yeah and that that four times more common in women that's that's really substantial uh and we'll get into that it seems to be tied to estrogen but we'll dig into that a little bit more in a bit. But having family members, they think there's some genetic component to it. If you have relatives that have depression or any kind of mental health disorder, it's,

you know, obviously it doesn't mean you will, but that could mean you might. I guess that's the way doctors say it. Yeah, you might got it. And not surprisingly, you're more likely to develop sad if you live in places in the far, you know, away from the equator, far north or south, where there's can be less sunlight or maybe, you know, in places like Seattle where there's just more gray days than others? Yeah, I was surprised. I couldn't find the other eight, the first eight, but Seattle was the ninth most affected city with seasonal effective disorder.

I would have thought it would be higher than that. I could not find the first eight. So I'm like, does this list really exist? Or was this just like a post-intelligence or made-up article? And do they tie in things like, or do they, do they, list things like Tacoma, like neighboring towns. Does that count as a different place, I wonder? That's a great question. What about Tacoma? Well, I just wondered, Tacoma's very lovely, but maybe Seattle might be a little more lively. Um, yeah, no, I could see that. No, no, everybody knows about

Tacoma. Okay, okay. It's been a long time since we picked down a particular city. Oh, I don't want to put Tac on our sites. Okay, we won't. Because, you know, you can't spell, you can't spell CETAC without attack. That's right. So what happens when you experience sad, seasonal affective disorder? I mean, most people can kind of come up with this idea of like what depression symptoms seem like, but there's specific ones that emerge with seasonal effective disorder. Yeah, I think, you know, generally what you will see like with most depression, listlessness, obviously sadness, interest in activities that you might normally like. You don't like as much.

You may have hard time concentrating, suicidal thoughts, if it gets really bad. Hopelessness, maybe guilt sometimes. And then some physical symptoms, like just a weight, like in your limbs sometimes. Yeah, like a lethargy, a fatigue. And those, yeah, that's kind of common among depression in general, but Winter sad has some extra symptoms like oversleeping or just sleeping. or just sleeping too much or more than you normally would, craving carbs, overeating, weight gain,

and then that fatigue, the low energy and tiredness. And all of those things, too, create like a feedback loop where, you know, if you're depressed and you start gaining weight and that kind of thing bothers you, you're going to be even more depressed because you just started gaining weight, in which case if you're an emotional eater, you might go eat more carbs, and gain more weight, and, you know, it just kind of goes on. So that's one of the difficult things about it is it's not just like, I'm depressed.

It's, I'm depressed, and now everything is set up because of this winter season for me to just keep getting more and more depressed while winter's going on. Yeah, and if you're sitting there thinking, like, oh, man, like in the wintertime, I tend to sleep later and I tend to eat and maybe drink a little more and gain some weight. and I'm a little more tired. Those are also, that's why sad is such a sort of a unique thing because that also just describes a lot of people in the winter. But there is a difference, and we're going to be pointing out those differences.

You mentioned summer was unusual because the summer sads, because it's very much opposite. And that goes for the symptoms as well because instead of sleeping in, you might have trouble sleeping. Instead of eating too much, you might have a low appetite, you might lose weight, you might be angry, anxious and agitated and irritable. Headaches is another one for Somersad.

Yeah, it's like winter said you go inward and are kind of closed off. And with Somerset, you go outward. But it's not in any, like, that doesn't mean you're just more sociable. It means like you're more agro potentially than you would be with like Winter Sad. So yeah, they're just kind of opposite. And yet they tie into, like you were saying, how people already are. Like, you go out more in the summertime.

You stay in more in the wintertime. So what seems to be the case with seasonal effective disorder is that it is a hyper or hypo version of a normal human biological imperative that we have learned as a society to try to ignore. And for some people, ignoring it is not really an option because it's so pronounced. Yeah, and inescapable. Yeah.

So there are basically four things. And like I said, if you feel like, oh, man, I kind of feel those things in the winter, too, listen to these four things because this is when you should see a medical professional, as if, one, if these feelings persist for days and days in a row, it's not like, oh, I just had a couple of rough days when it was, like, really rainy and cold. If your sleep and appetite patterns, like, really change is the second one. if you're coping with drugs and alcohol, that's a big red flag. And then the fourth one, if you feel hopeless or suicidal, for sure. And I think as far as diagnosis goes, you have to, I think it has to be for at least two years in a row, even though you did say you don't necessarily have it all years. You at least have to have it two years in a row at some point.

Yeah. And because it is essentially, if you look at the winter sad and summer sad, they're basically two ends of a spectrum, mania and depression, like people with bipolar two are definitely more susceptible to sad. And they might experience both types of seasonal, although again, just statistically speaking, they're much more likely to just experience the winter sad. Yeah, for sure. And if you do see a professional, they're probably going to ask you a lot of questions. You might even fill out an official questionnaire. There's no blood test or brain scan or anything. Like, like, you know, other types of depression.

That's the case as well. But you might get, they might rule things out. They might do like a thyroid screening or, you know, some other things just to make sure it's not something like physical going on. Right. So that's sad, everybody. And I think we should talk about where this whole thing comes from, they think, after a break. Chuck, our first break of 2026. Let's make it a big one.

You still got it. You still got it. All right. been learning some stuff about insomnia or aluminia um how about the one on borderline disorder better yet birth order heard that one before but it was so nice i learned it twice everybody listen up oh it's charles and Joshua it's stuff it's stuff it's stuff it's stuff it's stuff now. Hi, Kyle.

Could you draw up a quick document with the basic business plan? Just one page as a Google Doc and send me the link. Thanks. Hey, just finished drawing up that quick one page business plan for you. Here's the link.

But there was no link. There was no business plan. It's not his fault. I hadn't programmed Kyle to be able to do that yet. My name is Evan Ratliff. I decided to create Kyle, my AI co-founder,

after hearing a lot of stuff like this from OpenAI CEO Sam Aldman. There's this betting pool for the first year that there's a one-person, a billion-dollar company, which would have been like unimaginable without AI and now will happen. I got to thinking, could I be that one person? I'd made AI agents before for my award-winning podcast, Shell Game. This season on Shell Game, I'm trying to build a real company with a real product run by fake people. Oh, hey, Evan.

Good to have you join us. I found some really interesting data on adoption rates for AI agents and small to medium businesses. Listen to Shell Game on the iHeart radio app or wherever you get your podcasts. All right, so kind of like we were talking, it's kind of hard to diagnose this as when you should go to a doctor because a lot of people are just like this in the winter. And you're also sort of fighting, I think you kind of hinted at it, like a natural human intuition in a lot of ways. Because if you go back in time to the time where Tucktuck was roaming the earth, in the winter, they slowed down and they conserved energy because food wasn't around and it was cold. So they bunker down and there are some interesting theories around that, right? Yeah, they think it's possible that Neanderthals had like a real type of hibernation period in the winter.

Not, you know, like a bear necessarily, but something more pronounced than humans. And that interbreeding with Neanderthals may have produced seasonal effective disorder in some people. Yeah, like when Homo sapiens started hugging and kissing Neanderthals. That's right. Like in, what was it? Quest for Fire. Oh, man. There was some real realizations in that movie.

It was a, I mean, what an interesting movie, though, you know? Yeah, Ron Perlman. Yeah, he really, he's a good caveman. By the way, did a minute ago, did I say Bunkard Down? Mm-hmm. I meant to say hunker down. Is Bunker Down even a thing? I feel like it should be more than hunker down.

It makes more sense. Okay. I didn't even know. I heard you. made, like I grasped that you said bunker down, but it's so natural that it didn't even seem wrong. Yeah, and our Georgia Bulldogs, what they say for them is hunker down, you hairy dogs, I'm going to start saying bunker down, and everyone's just going to think I'm like a CIA plant

or something. Right, a NARC. Yeah. Oh, I can't talk about the dogs right now. I know, very disappointing. What a heartbreaker. Yeah. Okay, so you said something like that people back in Tuktuks age,

definitely slow down in the wintertime, right? Your body just changes. And that's still the case with humans. We have not evolved out of that. There's been studies. There was a 2015 study that found that the Simane in Bolivia and the San people in Namibia, who are in no way, shape, or form related,

ones in South America, one's in Africa, they both sleep longer in the winter and less in the summer. And you might say, like, well, duh, we all do that. That's exactly the point. There's some sort of biological mechanism. There's some sort of, like I said, imperative where you, without conscious thought and kind of without a choice, you slow down in the wintertime and you speed up more in the summertime. That's just what our bodies do. And because of this natural thing, it can go haywire, just like any other natural thing in humans.

when it does, that produces seasonal affective disorder. And they think they've got the mechanism to the whole thing down. Yeah, and that, you know, that's kind of evidence in this German study from 2023. They did a study, and caveat all this was it was a study already of people that had sleeping issues with disturbed sleeping patterns. Right. So it was kind of, you know, it wasn't just the general population. And interestingly, found that even if they were living in a place where it was mostly artificial, light, even then by season, their sleep cycles would vary. So it's not just like, yeah, if you live

out away from all the, you know, out in the boonies, away from industrialization and your circadian rhythms are really dictated by natural light, that would make sense. But they found that that took place even when you were just living a regular well-lit life. Yeah, even when you lived in a windowless, brutalist apartment in Munich. That's right. You wear a black turtleneck all year around. Oh, man. And then another kind of thing, like you said, that was a small study and it was of people who already had a sleep disorder, yet it backs up what everybody kind of anecdotally already knows, right? You sleep more in the season or you're more tired in the winter season. Another thing that's anecdotal but is backed up by study is that your appetite changes, right? Yeah. Some of it's

cultural where, like, you know, Christmas cookies are around. Sure. You're going to eat them. And Christmas cookies aren't around in March, say. Maybe some maniac makes like St. Patrick's Day cookies, but way more people make Christmas cookies than St. Patrick's Day cookies. So there are reasons that your appetite does increase is because there's more delicious stuff around. But we've also found that just by being in colder temperatures, being exposed to colder temperatures over periods of time,

hormone levels change in our bodies, and we crave more calories because as we digest them, we produce more heat, and that keeps us warm. We don't need bear skins anymore. Yeah, that's right. We need Buckeye balls. And Emily's aunt comes to town every Christmas now, and all her mom and her aunt and her sister and Ruby,

they all have a night-making Christmas cookies. Nice. Oh, dude. I did better this year than usual. I somehow managed to only put on five pounds. Hey, that's not bad for a Christmas season. From Thanksgiving to January 4th? Yeah, that's great.

That's not bad because usually that number is more like 12. So, and I found that that temporary sort of gain goes off a little quicker too. Yeah, it's certainly. Once you get back to reason, you know? Yeah, that's the key is getting back to reason faster than, you know, just not putting it off for the rest of the month of January. That's what I found. Yeah, you got, and the Buckeyeballs are gone and those little. old fashions really slow down after Christmas.

Man, those Buckeye balls. Oh, God. I made my mom's Christmas cookies, my mom's recipe, the one that I grew up with as a kid that had confounded me for years because I couldn't get it quite right. It was always too flowery. Okay. And in the last few years, I've learned enough about baking that I kind of figured it out on my own and I nailed it finally. Nice. Yeah.

Man, I've got to have some of those. It took, I'll make you some. Next Christmas, though. Yes. For sure. Not St. Patrick's Day, maybe. Don't do it. But you got me these cookie cutters that are all like kind of,

they're like sentimental between us, like different shapes. Oh, that's nice. And one of them is broccoli. So I have broccoli shaped cookie cutters. And I hate broccoli. Oh, I love that. That's fun. Yeah.

I don't have any. Oh, yeah, we were talking about how appetite changes. That's right. Here is one thing, though. You might think you've probably heard that, like, you know, suicide spike around the holidays because it can be such a tough time of the year for people. That is actually not true. In fact, they happen the least in December. They're more common in the summertime. Of course, in Australia, that's reversed because of where they are on how their

seasons run. So we're talking about the, you know, our hemisphere's perspective, obviously. Right. But I found that interesting. And it's good to correct the record because I think everyone always here's that. It's probably good in a way because anytime you're raising awareness on something like that, that's a good thing. But that's not true that they spike over the holidays. No, I feel like we've talked about that before.

And they think that maybe like just by people reaching out more during the holidays, you have a greater social calendar, typically just the holiday spirit can get to people. But then also there's some other explanations for why it might be more common in the spring or summer. months, like, you might just have more energy to actually complete suicide. Right. Another one that I thought was just horrible is that you, there are autoimmune conditions

like lupus or rheumatoid arthritis that are linked to seasonal allergies and that people who have those, are this overlooked population of people with a higher suicide risk and that that would account for it because your lupus is probably flaring up way more in the spring and summer than it is in the winter months. Yeah, for sure. And, you know, we've kind of hinted around about the length of day, and we're going to talk a lot about that over the next little bit. But it is, you know, it's intuitive and it's correct that the more intense that seasonal changes, as far as that length of day goes, the more likely you're going to have sad. There was a, I believe it was a meta-analysis from South Korea just last year in 2025. They did study 24 studies

with 30,000 total participants, so pretty robust. And for each one degree of increase in latitude, sad rose by 0.2% and just the winter blues by 0.32%. So, you know, one degree increase in latitude is obviously a little less daylight. It's like Jimmy Buffett said changes in latitude, changes in attitude.

Never thought about that. That's what he was talking about with seasonal effective disorder in that song. Yeah, he changed the title, though, because, you know, when you title things like Cheeseburger in Paradise, you can't title something, Seasonal Effective Disorder. Well, it was originally the song was titled Major Depressive Disorder with a Seasonal Pattern. Right, right. So, yeah, I think he was wise to change it as well.

So let's talk about it. You want to get into some of the causes? I've been teasing this, basically the entire episode, and I'm really kind of jazzed about this part. Yeah, I mean, here's where it gets science-y, because our old friends. obviously serotonin and melatonin show up, right? Yes. So just as a refresher, serotonin is responsible for things like mood, sleep, cognition, a bunch of other stuff.

But as far as seasonal affector disorder goes, those are the important things that serotonin does, right? Yeah. What's really cool, I didn't actually realize this. Sunlight hitting your retina actually triggers production of serotonin. It increases the production of serotonin. Right? So therefore, when we're exposed to less sunlight, there's a lower angle of the sun. You just don't get as much sun physically in the winter months. That means that your serotonin levels are actually less in winter than they are in the brighter spring and summer months. That's just a fact. It happens to everybody. But in most people, your serotonin transporter gene starts producing less serotonin transport. the stuff that goes in and gets the serotonin out of the synaps, right? That's right.

Which means that there's less serotonin, but there's also less transporters removing the serotonin that's there. So you keep about the same level of, say, mood that you would have in the summer months because your body is adjusting. What they found, just amazingly, is that there are two things that are screwed up with the serotonin and the serotonin transporter

that seem to be one of the major causes of seasonal effective disorder. So spill it, you're on a roll. Okay. So people with seasonal who get seasonal effective disorder, they have enough serotonin all year to keep them from being depressed, right? But just like everybody else, when they are exposed to less light, their serotonin goes down. But the thing that seems to give them seasonal effective disorder

is that their serotonin transporters don't also go down. Right. So like everybody else, they have lower serotonin during the winter, but they have the same amount of serotonin transporters. So there's less serotonin. And proportionately speaking, there's more serotonin transporters removing the serotonin, keeping it from working, which pushes them from non-depressed to depressive symptoms,

all because they're exposed to less light during the winter time. Yeah. And, you know, I mentioned women have it four times as often as men do, and it was tied to estrogen. And it looks like variations in estrogen levels can interact with those changes in serotonin and basically make it worse. And that probably is the explanation why women get it more. And, and, you know, perimenopause and menopause affect all that as well, which are, that's an episode we need to do for sure. Yeah. And also there, you know, we mentioned there's a genetic element, right? So it looks like that people, this generally speaking, who have at least one short allele in that serotonin transporter gene promoter region. I know that's a lot of words, everybody. The TLDL is, too long didn't listen. Is that right?

Yeah, nice. Is that there's a genetic component. So if you have that short allele, you're going to be more, more vulnerable. vulnerable to developing just regular depression to any kind of like, you know, life events or stresses like that or just depression period. But that short allele is also associated with those higher cert levels, the SERT levels in the winter. And that's where your increased level of sad is going to come on. Yeah. So that's serotonin. That's a big, big factor in producing seasonal effective disorder, as well as just any kind of major depression, right? Yeah. So melatonin is next.

And that, just kind of broadly speaking, as far as we're concerned, is the one that, you know, kind of makes you sleepy. Yeah, which, I mean, it can make you sleepy. It can make you lethargic. It can make you not want to go out. And all of this stuff, remember, there's a positive feedback loop here with the depressive symptoms that come on with seasonal affector disorder. The behavior they produce feeding back into becoming more and more depressed. Melatonin keeps you from wanting to do stuff because that's the way our bodies are so. set up to respond during the winter.

And it all has to do with the circadian rhythm, which as everybody knows, most people know, governs your sleep and wake cycle, right? Yeah. It also has to do with digestion. It has to do with body temperature and all sorts of other hormones. I didn't know this, but apparently it has to do with the release of cortisol, which we think of cortisol typically as a stress hormone full stop. And it is, but it also is a hormone that causes us to do more stuff.

to produce more energy. So when the circadian rhythm is not quite functioning correctly, it doesn't just make us sleepy. It actually makes us less energetic as well. And the whole thing, the whole circadian rhythm is controlled by a little part of the hypothalamus

called the superchaeismatic nucleus, or the SCN. Nice work on that one. I practiced it a couple times. Yeah, the SCN, and this is where we can throw a little German in there, it relies on sight gabers or time gibbers and these are just clues from the world around us telling you what's going on and mainly what we're talking about here is light

sunlight again hitting those retinas it travels to the the SCN and then that signals the pineal gland to release or produce that melatonin so the more light you have the less melatonin you have that's why you know you're not supposed to be looking at your cell phone or avoid like really bright lights before you try and get some sleep. But the TLDL here is it just means our bodies make more melatonin in the wintertime than the summertime. So you're going to be sleeping longer and probably a little more lethargic. Yeah, exactly. So serotonin plus melatonin being messed with, it happens to everybody, but most people's bodies respond in a way that regulates it and keeps it from becoming depression. Some people do not have that same.

way to regulate it and that's who has seasonal effective disorder yeah and I thought this is really interesting so it's you know we just said that if you experience sad then you're going to have a greater than average increase in melatonin in the winter than you know your your average person but this is really interesting you know we talked about sunlight coming through your retinas and that's the pathway that it initially travels right maybe a little on your skin but mainly through your retinas they found that your retinas actually actually react less to light in the winter compared to the summer. Your eye, Chuck, that is really interesting.

Thank you, Josh. And I guess before we break, we should talk about the third little thing after serotonin and melatonin, which are social and environmental factors. You know, if you have sad, when it's, when fall rolls around, you start to get that dread. You're going to have a negative emotional response to winter. It's not the cause of it, but that's part of that feedback. that feedback loop that you were talking about, you're like, oh, man, the days are going to get shorter if you live in the Pacific Northwest

or other places where it rains a lot and it's just more gray days that time of year, you just start to have that dread and that just feeds everything. Yep, yeah, it just makes it worse. And then, yeah, the whole thing is that feedback loop. Chuck, I'm going to do it again. I think we should take a message break. All right. We'll finish up with Sad right after this.

stuff about insomnia or aluminia um how about the one on borderline disorder better yet birth order heard that one before but it was so nice i learned it twice everybody listen up oh it's charles and joshua it's stuff it's stuff it's stuff you should not Hi, Kyle. Could you draw up a quick document with the basic business plan? Just one page as a Google Doc and send me the link. Thanks. Hey, just finished drawing up that quick one page business plan for you. Here's the link. But there was no link. There was no business plan. It's not his fault. I hadn't programmed Kyle to be able to do that yet. My name is Evan Ratliff. I decided to create Kyle, my AI co-founder, after hearing a lot of stuff like this from OpenAI CEO Sam Aldman. There's this betting pool for the first year that there's a one-person billion-dollar company,

which would have been like unimaginable without AI and now will happen. I got to thinking, could I be that one person? I'd made AI agents before for my award-winning podcast, Shell Game. This season on Shell Game, I'm trying to build a real company with a real product run by fake people. Oh, hey, Evan. Good to have you join us. I found some really interesting data on adoption rates for AI agents and small to medium businesses. Listen to Shell Game on the IHeart Radio app

Or wherever you get your podcasts All right So we talked several times About sad being a form of major depression Which means that it is highly treatable Actually thanks to our friends the selective serotonin re-uptake inhibitor, SSRI, or antidepressants. Apparently, well, butbutrin works really well to treat sad, but basically any SSRI is going to work.

One thing that stuck out to me, I believe that if you have seasonal effective disorder, but you're not, you don't have bipolar, you don't have major depressive disorder, it's just seasonal. I guess they suggest that you take SSRIs, you ramp up, in, say, like, the fall before it becomes winter, and then you wean off as springtime comes around. So they would have you on SSRIs, but not year-round because you wouldn't need them year-round. I thought that was fascinating, because that can be risky.

If you don't do it, right, it can be really risky. Yeah, and, you know, one of the things after that they suggest with all of these treatments is that you start before it hits, Like, you know, and depending on where you live, like when fall starts rolling around, maybe you start some of these therapies to see if you can head it off at the pass, like in the Old West. Yeah. But CBT is another thing that they suggest, like all cognitive behavioral therapy. It's basically, you know, trying to get you to change the way you're thinking about a thing. Right.

It might be a group therapy a couple of times a week over a couple of months maybe. But specifically in this case, it's like, let's try and get those negative thoughts about the upcoming season or the season that is upon you with positive ones and maybe do things like, hey, I know this is a thing for me. So I'm going to plan some things specifically for this winter that I know that I will enjoy. Yeah, like CBT seeks to break that feedback loop up. Right. So at least you're not getting worse and worse because of all the other cascading effects it has. Yeah, for sure. One of the other ones, like that 1984 study right off the bat, came identified a really great treatment for seasonal affector disorder that's non-pharmaceutical that you can do at home.

As a matter of fact, you can do it at the library. I saw that the libraries in Northern Ireland rent out light boxes. It's called Bright Light Therapy, uses very intense white light. don't worry there's a protective UV cover so you're not blasting your face you're not going to get a tan from it essentially but your retinas are going to pick up on that white light and so serotonin is going to increase your melatonin is going to not be so high and it can actually treat especially moderate forms of seasonal effect of disorder yeah for sure um the idea is you put this light on you don't just sit there and stare at it. You just kind of maybe do it in the morning,

15 minutes to an hour, maybe 45 minutes or so, cast it upon your face. This goes, is that funny? This goes all the way back, actually, to the 1700s. It was an Italian physician named Vincenzo Chiarugi, who way back then said, hey, if you're depressed, I think sunlight would help. So it's been a thing for a long time,

but now, you know, obviously they still say, get out in the sun if you can, but in a lot of places where there's limited light in the winter or just gray days like we were talking about. This is where the BLT, that bright light therapy comes in play. I saw they also make little hats, little visors. Oh, yeah. That just shine down on your face at all times. Nice. Like collective soul set. Yeah. I don't think you're supposed to, I think it's supposed to be limited still, though. You're not supposed to have that light on you at all times because it can it can disrupt your sleep and cause eye strain and fatigue and stuff. stuff like that. Right. Yeah, you don't want to overdo it for sure. And I think it's different for each person how much you actually need. But it does work. I know firsthand it works because you may use to get what I guess you would call sub syndromal seasonal effective disorder. She definitely didn't have major depression, but it was like she was impacted noticeably. And she found out about light boxes and got one and it helped her a lot. That's cool. I have friends that use these things just for

not even seasonal just for, you know, regular depression. And they say it helps them out. Dawn stimulation is another thing. And it's kind of the same idea, but it's like one of those alarm clocks that slowly starts brightening your room over the course of like 30 minutes or so as you're waking up.

So, again, tied into the circadian rhythm of rising with the sun's rise. Do you remember that alarm clock from the 70s and 80s that, like, it would light up? It had a picture of, like, I think, like a fence out in the old west, and the sky would go like dark blue. It would, like, it would change the color of the sky on the alarm clock picture depending on what time of day it was.

You don't remember those? No, I don't think I've ever seen those. They were amazing. My oldest sister had one of those. I would love one. I don't know what happened to that. Probably broke. Yeah, my brother had one of those clocks, the alarm clocks,

that had the, like a Rolodex, it would flip the numbers around, like mechanically. Oh, neat. Yeah, those were fun. Yeah, the one I always had was like the the R, R, R, R, R, R, kind. Oh, man, no. Really?

Yeah, when I was a teenager, that's what I needed. Or the two bells with the hammer. I had one of those, too. Oh, man. There was a period where I had the one that went, uh, uh, uh, wouldn't do it. So I had to switch over to the two bells one. Oh, yeah.

Have you always had a hard time waking up like that? Yeah. have i i don't anymore but yes i used to when i was a teenager well because i get emails from you at like 5 30 in the morning like what the hell are you doing you farming i've seen i've milking the cows and email okay at the same time sometimes um i have decided that getting up at five is way too early for me so good i'm i'm doing six now hey that's reasonable it is seven sometimes if i'm feeling frisky. They had a really late night the night before?

Yeah, I went to bed at 10. We should mention vitamin D, speaking of cows, because vitamin D deficiency does correlate with more likelihood of having or developing sad, but they haven't found any good, hard, consistent evidence that vitamin D supplements can help a lot. There's one place, remember you said that high latitudes, the higher the latitude, the more negative the attitude, the likelyer you are to have seasonal, a factor of disorder, that does not hold true, at least in some parts, some of the most extremely northern parts of the world, in particular, is a town called Tromsa, Norway that is very northern, it might be the most

northernmost city in Norway. It's really high up there. Suffice to say that they are absent from sunlight, I think two full months out of the year. Oh, man. Like, nothing like the sun comes out. I mean, I think it might get as much as it would get, like, before sunrise on a normal day. And they go like that for two months. And yet, the rates of seasonal affector disorder are much less in trauma than you would expect. Yeah, it seems to be, because they've done just sort of studies and questionnaires, and people,

there agree with statements like, I love the coziness of the winter months. Winter brings many wonderful seasonal changes. They don't agree with winter is boring when winter is limiting. So it seems to really be a lot about the attitude. And, you know, I think if you live there, a lot of people probably don't just move there. It seems to be a place where you're usually from. Or maybe people do move to one of the most northernmost cities in the world. I'm sure it happens. But generally, if you have grown up in a place and that's the thing, everyone knows that's the thing. And so there are probably many, many events and traditions and activities that they do to thwart that.

And it seems to work because they get into their skiing, they get into their winter hiking, they get into their cozy drinks and their warm blankets and their fireplaces. And it seems to be that they look forward to that stuff. And it bears out by them not having a prevalence of sad there. It's kind of interesting. Yeah. And some people point to that as evidence. They say that there's no such thing as sad.

That just does not make sense. If sad is this response to a biological imperative that happens every year among people who are maladjusted for that imperative, then that just should not be the way in Tromsa. And there was actually a study from 2016 from researchers at Auburn Montgomery, the University of Auburn and Montgomery. And they studied CDC data and they found no seasonal variations. in depression symptoms. And it was a massive population that they studied. And, I mean, if there is such a thing as seasonal effect of disorder, then there should be an increase in the winter months and they didn't find it.

That does not seem to be the consensus among the scientific community. As a matter of fact, I wanted to go click on the link in the Scientific American article that we were checking out. It exploded. It was gone. It couldn't find it. Oh, wow. So it made me wonder if they quietly retracted it or maybe it's just a broken link. You never can tell. But for the most part, if you look up seasonal affector disorder, every reliable website in America like Johns Hopkins or Harvard Health or Cleveland Clinic, Mayo Clinic, I could keep going.

they are they are all all in on seasonal affective disorder I'm uh now I'm picturing just like a couple of scientists in a ditch being shuffled over with lime right um so just one thing before we stop it has nothing to do with Norway really but it reminded me I saw a there's a good true crime um doc I don't know if it's a docu drama but it's based on in real life and it's Danish It's called The Investigation. It's so mellow. The investigation.

I love those, I love stories set in those parts of the world. I love Danish filmmaking and Norwegian filmmaking. You'll love this. It's like there's at least one episode where almost the entire time, nothing happens. And they just show nothing happening. But it's really good. It's really engrossing. So I would recommend it.

Awesome. Chuck said awesome. That means he just triggered the first listener mail of 2026. everybody. That's right. This is from Megan and Michigan. Hey, guys, thank you for the many years of engaging in interesting content.

I first started listening in 2012 when I moved out of my home state and would download episodes onto CDs. Nice. Wow. That is, wow, I feel old. Well, this will make you feel old, too, to pass the time on the long drives

in my old cavalier. Wow, wow. They don't still make the cavalier, do they? I don't believe so, no. I think they buried them with those Auburn and Montgomery researchers. Well, 2012, I'm surprised she wasn't in a Camry. I just listened to your dolls episode, guys.

I had to write in. I have three kids, and they have at times acted out scenarios with dolls and toys that would have been very disturbing if I had not been prepared that it was very normal and healthy, actually. The most recent example is when my five-year-old came into the house and told me that he and his three-year-old sister had made gravestones in the backyard because their twin baby dolls had died. Oh, my.

Even knowing it's normal, I do have to take a deep breath and remind myself that part. of raising emotionally healthy kids is letting the process through play. Still, I was a bit relieved the next day, and they threw a big party for the baby's first birthday. So she skips out the part where they dug them up out of, they exhumed them from the grave. Thanks again for bringing so many topics and perspectives to light, while somehow keeping things humorous and upbeat. Looking forward to learning more in 2026.

That is Megan and Michigan. Nice, Megan. Thank you for that. That was a great, great email. And God bless your kids for being awesome. For sure. If you want to be like Megan and tell us about your awesome kids, we love that kind of thing. You can send it off to Stuff Podcasts at iHeartRadio.com.

Stuff you should know is a production of IHeartRadio. For more podcasts, My Heart Radio, visit the IHeartRadio app. Apple Podcasts are wherever you listen to your favorite shows. This is an I-Heart podcast, guaranteed human.