Do We Know How Psych Meds Work?

Do we know how psych meds work? Yes and no - diagram of a neural synapse

Sometimes you’ll hear people argue that doctors don’t know how psych meds work, and therefore they shouldn’t be used. However, there’s a lack of clarity to these statements that, at least in my opinion, casts psychotropic meds in an unfair light.

What is the mechanism of action?

If we’re going to about how medications work, that incorporates a couple of distinct concepts.

Part A is what the drug does in the body. What receptors, enzymes, etc. does it interact with, and what is the nature of that interaction?

Part B is how that produces the therapeutic effect. Say we know drug A binds to receptor X – so what? How does that interaction with receptor X lead to a therapeutic benefit?

For most psychiatric medications, science has done a pretty good job of establishing Part A, i.e. what receptors they act at and what they do while they’re there. So to say we don’t know how they work, full stop, is misleading.

What we may be missing is the Part B, the so what.


Let’s look at ketamine as an example. It’s been around for a while as an anesthetic, and it’s known to work on NMDA and AMPA receptors, affecting the activity of the neurotransmitters glutamate and GABA. Great, so what? Well, it appears to boost levels of the protein brain-derived neurotrophic factor (BDNF), which promotes the creation of new synaptic connections in the brain.

Okay, but what’s the connection to ketamine’s antidepressant effect? That’s where things get more iffy, especially since other drugs that act the same way at NMDA receptors don’t have the same therapeutic effect as ketamine.


Another medication where there’s an element of mystery is lithium. Lithium does a lot of different things: it affects the enzyme inositol monophosphatase, it affects G-proteins that move substances in and out of cells, it regulates gene expression for growth factors, it affects downstream signal transduction cascades, and it affects the neurotransmitter GABA.

So, lithium gets around. Is it known exactly what part of its activity in the human body produces the therapeutic benefits? Nope. Does that make it a sketchy medication? No. Sure, it has side effects, but like any other medication, there needs to be an individual weighing of pros and cons.

How does this matter?

The key point here is that the medical field isn’t throwing meds at us without having any clue what they do in the body. And sometimes, the mechanism of action of the side effects is actually better understood than the link between the mechanism and the therapeutic effects.

From a pragmatic perspective, what matters is whether or not a given individual gets the desired therapeutic effect from a given drug. When ketamine finally gets Health Canada approval, I’m certainly not going to be waiting around for science to figure out which component of its activity is responsible for the therapeutic effect. I just want to feel better.

For more posts on psychiatric medications, the Psych Meds 101 series covers:

You may also be interested in the post Why Do Psych Medications Stop Working Sometimes?

book cover: Psych Meds Made Simple by Ashley L. Peterson

Want to know more about psych meds and how they work? Psych Meds Made Simple is everything you didn’t realize you wanted to know about medications.

It’s available on Amazon and Google Play.

Ashley L. Peterson headshot

Ashley L. Peterson


Ashley is a former mental health nurse and pharmacist and the author of four books.

28 thoughts on “Do We Know How Psych Meds Work?”

  1. I tried lithium, but it made me crazy thirsty and gave me massive hiccups, which are the same side effects I have to vicodin. The body is a crazy thing, but I trust the medical professionals who have been to school for a long time to have some idea how to help. It’s like my car…I have no idea how it operates and I get it checked out as necessary, but I trust it’s going to do the job without my ignorance getting in the way.

    1. And maybe one day we’ll get to the point where it can be predicted how a particular individual will respond to a certain medication, but just because we don’t know that yet doesn’t mean we stop putting gas in the tank!

  2. I think it’s often some sort of trade-off. Medication can often help to prevent the worst and literally save lives. But I am somewhat skeptical when it comes to over-prescription because some of the side effects can be quite detrimental. There are numerous studies which indicate that antidepressants don’t do much in cases of mild and medium depressions but other therapeutic interventions have higher impact. In severe cases of mental illnesses like major depression, schizophrenia, bipolar, etc. medication definitely has its merits though.

    1. Medications are definitely not the right choice for everyone all of the time. But that’s something that’s better done with an individual weighing of pros and cons rather than broad assumptions about medications or any other treatment strategy.

  3. Another interesting read! I was thinking about a post about medication but from a different angle than you took – oof!. I was never happy to take medication, not even with fever of 39.8°; I felt so bad due to depression I would have tried everything! When you’re ill, you do whatever it takes to get better. I am very interested in how medication works and science is always improving (I hope that people see the value in that and the investors too!). I’m pro, I think it’s pure stupidy to throw away what we already have and to go 10 steps back because ‘somebody thinks it’s all a scam’. I believe we will have a better understanding of medication and the body in the future. But I can also empathize with people who suffer a lot due to side effects. Sometimes the side effect have a very big impact on daily and social functioning and I believe doctors should be open to try to adjust a little (if possible off course) to better cope with or to dimish those effects. I honestly didn’t know it was a real discussion, ‘if we don’t know how they work, maybe it’s not good afterall’. Nope, nope and nope!

    1. I agree that prescribers definitely need to be more responsive to people’s concerns. If a patient finds a medication intolerable and the prescriber doesn’t want to budge, that’s extremely unprofessional. Paternalism and authoritarianism may have been the name of the game back in the day, but there’s a better way.

      1. Maybe it is also very good, in that way, that you bring attention to it because I believe, when you have an open and honest conversation about it. Really think together about the pros and the cons of medication + the situation, maybe some people will conclude that medication isn’t that bad aferall and maybe some prescribers can budge a little. It still is a bit of a taboo I think. I enjoyed your post very much!

  4. What a coincidence… I just commented on your book in the comment section of the “Working on Us” post.
    I refer to your book quite often, it’s a valuable asset to have when trying to understand the medications and how your body reacts to them.
    I thank you so much for creating this book!!!

  5. Very nice post, I think it goes well with your “Working On Us” response. It’s unfortunate that when people don’t understand how something works, they demonize it. My sister once told me to “never take antidepressants because they make people homicidal” -__-

  6. There’s a solid research evidence base to support it’s use in bipolar disorer and as an adjunct to antidepressant therapy in people with major depressive disorder, and also for mood symptoms in schizoaffective disorder. It’s also been show to be particularly effective in reducing the risk of suicide. Whether it will work in a specific individual with those conditions or cause intolerable side effects in a specific individual is the same with any other medication – you don’t know until you try it. It doesn’t tend to be used that often in major depressive disorder, but that has more to do with concern about side effects than lack of efficacy.

  7. That is a question I never thought to ask. I used to take meds and was explained what it did. I think not know how it did it while in my body could have told me why I had side effects but someone else didn’t. Is it an individual thing?

    1. How the drug acts is consistent, but how the body responds to that action is variablefrom one individual to the next, both in terms of therapeutic effect and side effects.

  8. I use to be so scared of medication. All of the side effects really sucked. Some would sedate me so much I was emotionally numb. Some I thought changed my personality. I think my medication just makes me a weirdo. But I never cared to know how they actually worked. This post sparked an interest. Thanks.

    I now realize that medication really helps me and without it I’m in a lot worse shape than I am in now. So now I tell the doctor to give me whatever he wants bc I trust him.

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