Posted by Racer on September 8, 2004, at 12:36:09
In reply to SSRI vs SNRI ------HELP, posted by woolav on September 7, 2004, at 17:57:35
The reason medication is still trial and error is that we're not just chemical reactions. We're entire organisms, and we have those big brains with a lot of connections between the emotional centers and the intellectual centers, which are both connected to the more primitive 'animal' sections of the brain. In other words, none of this is entirely a question of hitting certain receptors and everything changes overnight.
All of our disorders have a biochemical component, along with a psychological and usually a social component. ("The whole is greater than the sum of its parts...") In order to find a medication or combination that works for each individual, a doctor has to try a variety of substances, because everyone is going to react differently. How you react to a medication is going to involve all sorts of things: how you feel about your disorder, your diet, your lifestyle, your tolerance for the adverse effects, etc. Something as simple as whether or not you drink soda will effect whether or not a specific drug works for you. And something as complex as your social support network will also affect how well a medication works -- or even if you can get through the adjustment phase for a specific drug. The best doctors "get it", but some seem to think that they're supposed to be Pure Scientists and prescribe based on the neurotransmitter systems targetted by a specific drug.
As usual, I can only give you a very shallow overview of the differences: serotonin is used throughout the body, with something like 90% of it being used by your gut; norepinephrine is a bit more of an activating system, and I believe it's part of the system that eventually leads to adrenaline (that part is way vague in my poor excuse for a mind right now). The older anti depressants used a sort of scattershot approach, and hit all three major neurotransmitter systems: se, ne, and da. DA is pretty much the "blissful" system -- it's involved in drug abuse, and that whole excitement-junkie thing some people get into. Precisely what the other two do is not in my conscious thought processes right now, but someone else is sure to jump in with it.
The bottom line, though, is that none of this is an exact science. The doctor can't do a blood test and say, "OK, your DA is high, and your NE is a bit low, but your SE is through the floor, so we'll use [x]" because it just ain't that simple. The best they can do is to try the first line drugs -- usually the SSRIs, sometimes the SNRIs, and then experiment until something clicks. The best combination isn't necessarily the drug that 'fixes' your depression/anxiety the best, but the one that manages it best with the fewest untoward effects. (After all, there's no point in medicating your depression into total remission if it also gives you such severe diarrhea that you can't leave the house, right?) It's a balancing act at best, and a lot of the choices the doctors make are based more on the safety of the drugs in overdose or in side effect profiles than on what the medication actually does in the body.
To make it even harder, even the selective drugs out now still affect more than just the specific receptors in the brain. If they target, say, serotonin receptors, they'll target them in the gut and in the mast cells as well as in the brain. That means that none of them are entirely benign. They'll all have side effects.
As for Cymbalta versus Effexor, while they both target both SE and NE, the Cymbalta is more balanced in its action, and the molecules themselves are quite different. They may have the same end effect, but through very different means. Even if it were a closer relationship -- like that of Celexa and Lexapro -- the whole picture may still be very different, and if one fails utterly for an individual, the other may still work.
If it helps any, Effexor was pretty mixed for me, and I wouldn't try it again to save my life. (I'd beg for euthanesia first.) I'm trying Cymbalta right now. They are different. Sure, there are similarities, and I'm not loving it at this point, but I'm also not giving up on it, either.
So, since we're more than just a punch-card mechanical and chemical system, trial and error is the only way to go. Maybe that'll change one day, but I doubt it. A lot of medicine is more art than science, and this is an area where that's most apparent. I guess if I were in an advice giving mood, I'd say sit down and make a list of the symptoms you most need addressed, in order of priority, and discuss it with your doctor. The clearest picture you can give him will give him the best chance of guessing right. (And don't forget that some of the symptoms may be more physical than psychological. Maybe, for instance, you don't need a benzo to relax your mind -- maybe you need something more like a muscle relaxant for anxiety. He may not recognize that unless you can tell him what specific symptoms are involved in your own, idiopathic anxiety.)
I know it's not quite what you asked for, but I hope it helped a bit anyway. Good luck.
poster:Racer
thread:387767
URL: http://www.dr-bob.org/babble/20040904/msgs/388049.html