Posted by linkadge on February 21, 2007, at 20:58:11
In reply to Re: opiates for depression, posted by Quintal on February 21, 2007, at 17:45:07
>I think it's hard to tell link, since there are >no drugs that specifically release dopamine only >in the frontal cortex (that I'm aware of) that >could prove it conclusively.
Caffiene is an example of a stimulant drug which increases dopamine release much more in the frontal cortex than in the neucleus accumbens. While caffine is not patentable, it is probably the number one choice for ADHD for a number of undiagnosed.
But, my point was that there are plenty of drugs that are eupohriants (ie NAA dopamine release) wich are not effective for ADHD. So, the effect of ritalin is not simply due to euphoria.
Just like, for a while people thought the mood effects of amphetamines were inseperable from the weight loss properties. Amphetamine derivitives like fenfluramine however seem to proove this assumption wrong.
>The performance of treatments for ADHD that >operate selectively via the noradrenergic >system, like Strattera seem less impressive than >those that (perhaps incidentally) increase >dopamine release in the nucleus accumbens.
Thats probably because straterra doesn't increase frontal cortex dopamine as much as it does frontal cortex noradrenaline. This drug doesn't make a lot of sense for ADHD since a number of studies indicate noradrenaline is hyperactive compared to dopamine in ADHD. (but thats beside the point)
>I think to some significant extent the increased >efficiency and tolerability of amphetamines used >to treat ADHD is due to increased desire and >greater capacity to feel reward caused by >release of dopamine in the nucleus accumbens, as >well as increasing attention span and >organisation etc, by releasing dopamine in the >frontal cortex. I say this because again, drugs >that increase attention span alone and cause >little if any euphoria, like Strattera seem to >be less effective (and less well tolerated) >overall.
Well, I'd like to comment. For starters we only really have Straterra, which as I mentioned above doesn't really increase frontal cortex dopamine so I wouldn't even use it as a comparitor. Certain supplements like omega-3 have utility in ADHD. The 0-3 fatty acids increase frontal cortex dopamine, but do not directly activate the reward systems. So, I'd say we need more drugs in order to fully know for sure.
Another argument that I would make is that many people who are trying drugs like strattera have already been primed to the reward of ritalin. As such, they are unlikely to find other drugs as effective.
Only time, and more test drugs will fully determine whether activating the reward systms is actually necessary for ADHD drug effect. One would also need to ascertain wheather the reward system in ADHD is actually dysfunctional, because we do know that long term stimulant treatment can make the reward systems dysfunctional.
Another consideration is that ADHD drugs can continue to work, long after the subjective high has subsided.
Kids who take ritalin for years, are unlikely to be getting any buzz from it, but it still helps their attention.
>I really think a drug that's subjectively more >pleasant in its effects will have more treatment >responders, because more people will be willing >to persevere for the full length of the trial >even if the actual benefits aren't that good.That is certainly true.
>We already have a whole gamut of antidepressants >that supposedly treat depression without causing >euphoria. They seem to be less effective overall >than those that do cause euphoria, especially >for treatment resistant depressives, and that is >what most of this debate has been about.I agree. But, all I am saying is that with some of these drugs, even the ones that cause euphoria, there may still be undetermined mechanisms of theraputic action that could be unrelated to euphoric properties. The neucleus accumens quickly adapts to chemical alterations, so I would argue that if a long term theraputic response is attained, then there is likely something else going on.
Linkadge
poster:linkadge
thread:734151
URL: http://www.dr-bob.org/babble/20070219/msgs/734962.html