Serotonin is a molecule that makes people feel satisfied with what they have. And it does much more than that. It interacts with many other systems throughout the body, which is highlighted by the fact that it acts as both a neurotransmitter (i.e., communicates locally in the synapses between nerve cells) and hormone (i.e., communicates distally by circulating in the blood). Its complex nature helps explain why habits that support its healthy functioning can have substantial downstream benefits.

Serotonin is primarily part of a reward system that includes dopamine and cortisol. I’m starting with serotonin because the healthy habits are easier to implement than for dopamine, which will be in later posts. Cortisol, while healthy in some cases, is an inhibitor for both serotonin and dopamine, so chronic stress can disrupt both systems. Stress will be discussed extensively in later posts, too.

To produce serotonin, the body needs tryptophan, an essential amino acid (meaning you have to get it from food). Most people get plenty of tryptophan if they get enough protein, but it is more abundant in meat and dairy than plant-based food. Oats are a good source in plant-based diets. In turn, serotonin is used to produce melatonin, which is important for healthy sleep.

Rule 1: I get at least 20 minutes of direct sunlight a day and avoid bright screens after dark.

Sunlight is critical for healthy circadian rhythms that allow you to be alert and energized during the day and calm and restful at night. One component of this cycle is the relationship between serotonin and melatonin. Sunlight, and any other bright light, signals your brain to produce serotonin and inhibit melatonin. It’s best to get sunlight outside because windows diffuse the light too much, and it’s best to be without sunglasses, which changes the quality of light. I like to go for a walk shortly after waking up to get sunlight before it’s too overhead and bright.

For the same reason, it’s important to avoid bright light after dark to allow serotonin to be converted into melatonin. I know what you’re thinking, I said these habits were easy and staying off screens after dark is not easy. Screens are fine as long as they are dimmed or far away. I use the night time setting built into most operating systems to dim my computer screen at sunset, and I use the Twilight app on my phone. It might take a little bit of adjusting, but once you’re used to it, you’ll be blinded by any undimmed screen. Some people also wear glasses that block blue light (blue blockers) after dark, but they’re expensive and not always effective. As always, your experience may vary depending on how sensitive you are to certain cues.

Rule 2: I practice gratitude for 5 minutes a day.

A 5-minute gratitude practice is the most simple habit that has most profoundly affected my mood. All it takes is sitting for 5 minutes and thinking of all the things you are grateful for. You can keep a journal, but I never have. Instead, I like to make it an excuse to stay in bed an extra 5 minutes. I like using a minimum time or minimum number to encourage me to explore beyond the obvious (e.g., comfortable house, stable job, supportive partner) and appreciate

• random acts of kindness (e.g., that person went out of their way to do something nice),
• things I take for granted (e.g., clean water on demand, internet, toothpaste), and
• things that are counterintuitive (e.g., this difficult experience has helped me to grow).

Taking time to appreciate the things that make my life better activates this satisfaction-based reward pathway. Many ambitious people are worried that a gratitude practice will make them too satisfied with what they have and take away their drive to achieve, but it often has the opposite effect. A healthy serotonin system supports a healthy dopamine system, aka the drive to achieve. Take power poses as an example. Power posing is the practice in which you take up a pose that exudes power, such as standing like a superhero, before an important presentation or meeting to carry over feelings of confidence or reduce stress. There was a lot of controversy due to originally attributing this effect to a rise in testosterone, which didn’t pan out, but power posing does have a reliable positive effect. That reliable positive effect is consistent with serotonin/dopamine research in social animals.

Social animals, for better or worse, evolved to live in social hierarchies. For stable and harmonious social hierarchies, we needed a mechanism to track our social status. This mechanism is about as primal as you can get, and it involves the levels of serotonin and dopamine. This mechanism is so primal that it works automatically based on outcomes rather than context. If you put two rats in a tube so that one has to win by pushing the other out, the winning rat will have higher serotonin and lower dopamine than the losing rat. This is true even if the experimenter pushes the winning rat or pulls the losing rat, and they take no action to win or lose. Regardless of how it won, the winning rat registers higher social status and is more likely to win the next round, and the losing rat, regardless of how it lost, registers lower social status and is more likely to lose the next round.

The serotonin and dopamine levels contribute to experiencing a winning streak or a losing streak. This effect is found across social animals. There’s even evidence that imposter syndrome is linked to low serotonin levels. It’s a cycle that feeds on itself, and gratitude practice can be a simple and effective habit to disrupt it. The best part of a gratitude practice is that no one has to lose for us to trick this automatic mechanism into registering that we’ve won.

For more information about gratitude practices, watch this Therapy in a Nutshell video that focuses on the changes it makes to your brain. For more blog posts about wellness, return to the wellness series page.