Primer: Neurotransmitters and Hormones
January 2, 2023
As you learn about ADHD, you might hear about dopamine and other neurotransmitters. But... what exactly IS a neurotransmitter? This article is very accessible, and has resources for beginner, intermediate, and advanced levels of further learning at the end.
The following is a simplified but useful explanation of some of the neurotransmitters (and some of their hormone alter egos). The information here is true about all human brains, regardless of whether you have ADHD or not. I’ve included some references for reading at various levels at the bottom, both in case you want to learn more, and to give credit to some great resources and educators out there.
Neurotransmitters are like text messages that get sent from one nerve cell to another. One cell sends short text like, “calm now” or “danger danger!”, and if all goes well, the next cell receives it, even though there’s a little gap between the cells called a synapse.
If a cell sends a packet of adrenaline, the message might be something like, “zoom!” Depending on the context, that message might mean we need to run faster because a bear is chasing us, or that we’re having a great time on a roller coaster. Either way, adrenaline is a neurotransmitter that sends the message: it’s go-time! It affects systems that you might need to really accomplish something or survive an encounter with something scary.
Dopamine is another neurotransmitter. Its message, “good stuff!” might mean that we’re doing something fun or we did a good job… or it might mean that there’s something delightful ahead and so it might motivate us to go get that good feeling.
Dopamine and adrenaline often have overlapping jobs in the brain. Loosely, these are molecules that say, “get up! Let’s go! Do the thing!” and either “This will be great!” or maybe, “This is probably dangerous/exciting!”
Adrenaline has another job outside of being a neurotransmitter: it’s also a hormone. So while neurotransmitters pass between nerve cells in the synapses, hormones travel in the bloodstream and spread messages throughout the body. You could think of hormones like a very short company-wide email.
When you encounter something exciting or scary or stressful, the adrenal glands send out a big message to the whole company (your body) that says, “ALERT!” If the context is a fun one, like an exciting game of laser tag, this can be interpreted as fun; you might interpret that same feeling differently if you get the alert message because someone jumps out and scares you. No matter why it happens though, as a hormone, adrenaline’s job is to get you ready to go-go-go. Your heart rate will increase, your pupils will get big, and your body will prepare to survive.
So if the adrenal glands get a text from a nearby nerve cell saying, “go go go!” they send out a company-wide email saying, “alert!”. Both use adrenaline but in different ways!
Adrenaline and dopamine aren’t our only neurotransmitters- we have many! Another one that’s good to know about is serotonin. Serotonin’s message might be something like, “cozy.” It suggests that we relax and enjoy; think about the feeling you get after a good meal or a long hug. You could also think of it as, “taken care of,” “fed,” or “safe.” It might not surprise you to learn that the hormone melatonin (which helps us get sleepy for bedtime) is made from this neurotransmitter!
And finally, just in case you’re wondering, adrenaline is also known as epinephrine. You may also have heard of norepinephrine. Both have very similar functions, and both are actually made from dopamine.
To recap (remember: this is a simplification):
Neurotransmitters are sent across the gaps between nerve cells to send messages.
Adrenaline prepares you for action
Dopamine gives you a feeling of reward and/or anticipation
Serotonin gives you a feeling of satisfied contentment
Hormones travel through the bloodstream throughout the body
Adrenaline prepares you for an extreme situation
Melatonin prepares you for bedtime
For those looking for a simple explanation of dopamine, norepinephrine, serotonin, and melatonin, Andrew Huberman's podcast (Huberman Lab) has a great explanation in his podcast from Jan 18, 2021 (Using Science to Optimize Sleep, Learning & Metabolism \ Episode 3). The explanation about the neurotransmitters and hormones starts at about 31:15. It’s very accessible!
More detailed information about Noradrenaline (very similar to adrenaline).
Detailed information about norepinephrine and epinephrine (aka noradrenaline and adrenaline)
Really sciency and interesting information about dopamine and noradrenaline: