Posted by Racer on May 26, 2008, at 10:13:25
In reply to Can we really choose drugs based on mechanisms?, posted by SLS on May 22, 2008, at 6:48:38
> Can we really choose drugs based on known mechanisms?
>
> Are we really able to deduce our individual psychobiological abnormalities?
>I don't think there's enough information yet known for drugs to be chosen by mechanism. Just the fact that the SSRIs have such different effects, despite their related mechanisms, suggests that there's more to it than simply boosting one single neurotransmitter.
On the other hand, I do believe that past experience with medications can help suggest directions to explore. For example, I have done best on medications which target norepinephrine, and had problems with serotinergic medications. I'm much more willing to try the noradrenergic/dopaminergic medications than anything serotinergic, based on my own experiences. I don't think that's the same thing as being able to deduce my own biochemical eccentricities, though.
In the course of my readings, I've found some interesting articles that make me much more skeptical about any putative one-to-one relationship between medications and neurochemicals. For instance, did you know that Ritalin reduces the ADHD-like symptoms in dopamine knock-out mice? These are mice without active dopamine receptors -- and yet, we discuss Ritalin as a dopaminergic medication. That seems to suggest -- strongly -- to me that boosting the action of dopamine is probably not the solution to ADHD-like symptoms, it's probably not how Ritalin actually works. Or, at least, it's not the whole story.
After years of reading that glial cells are the neurological equivalent of styrofoam packing peanuts, suddenly we know that they're actually active in the brain. Dopamine was thought for decades to be nothing more than a precursor to norepinephrine. Overactivity at certain serotonin receptors in the Central Nervous System is associated with anxiety, and yet SSRIs are effective for anxiety for many people. I don't believe there is enough information yet known to say for certain that any particular mechanism is The Cause of anyone's symptoms.
What's more, I don't believe that there is one disorder called Depression. I believe that there are clusters of symptoms which we group together for convenience sake, and call Depression. It may be that your depression is related to one neurochemical, and mine another. It may even be that none of the catecholamines are involved in some cases of depression -- perhaps it's an abnormality of the calcium channels on your neurons, and a calcium channel modulator would be your best bet. Perhaps glutamate is the culprit for some cases of depression. Maybe the problem isn't at the synapse at all, but somewhere downstream in the synthesis process -- maybe I can't create serotonin from tryptophan? Neuroscience just does not yet know enough to say with any degree of certainty.
And yet -- I do believe that prior experience with medications of various mechanisms can suggest directions to explore.
How's that? "No, but..."
Great topic, Scott -- and now will you share your answer with us?
poster:Racer
thread:830457
URL: http://www.dr-bob.org/babble/20080519/msgs/831198.html