Time for AD:s to show effect - does the brain re-growth theory hold?
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From: John on 4 Jan 2006 18:34 Hi, For most anti-depressants (AD:s) a time frame of about 2-5 weeks is claimed for the AD to show it's full effect. But according to several theories, AD:s are supposed to work by indirectly altering the amount of brain growth factors such as BDNF (Brain Derived Neurotrophic Factor), thereby causing re-growth of the parts of the brain that have "shrunk" due to depression. If this is true, then wouldn't the full effect of an AD take several months or more to show it's full effect? After all, if depression has caused certain parts of the brain to "shrink", wouldn't it take more than 2-5 weeks for an AD to cause full re-growth of the brain to a pre-depression state?
From: Nom dePlume on 4 Jan 2006 18:38 "John" <nospam(a)no.where> wrote in message news:43bc59fe$0$28936$6d36acad(a)roc.nntpserver.com... > Hi, > > For most anti-depressants (AD:s) a time frame of about 2-5 weeks is claimed > for the AD to show it's full effect. But according to several theories, AD:s > are supposed to work by indirectly altering the amount of brain growth > factors such as BDNF (Brain Derived Neurotrophic Factor), thereby causing > re-growth of the parts of the brain that have "shrunk" due to depression. If > this is true, then wouldn't the full effect of an AD take several months or > more to show it's full effect? After all, if depression has caused certain > parts of the brain to "shrink", wouldn't it take more than 2-5 weeks for an > AD to cause full re-growth of the brain to a pre-depression state? Antidepressants that increase *serotonin* (specifically) seem to promote new growth of both serotonin receptors and neurons. The time scale for receptor growth is about two weeks, and for most people, this correlates fairly well with the onset of mood improvement. That's not to say that further improvement won't happen in the following weeks, but the *onset* of improvement usually happens around the two week mark, giver or take a bit. I suspect (but don't believe anyone has demonstrated) that persistence of the new growth is what allows some people to retain the antidepressant benefits after stopping the antidepressant. Increases on the concentration of other neurotransmitters (i.e., norepinephrine, dopamine, GABA) seems to be felt very quickly, within hours to days, which suggests that it is simply the increase in concentration that produces the effect, not new receptor growth. If so, then stopping the medication should stop the benefits, which is indeed what I've observed. -- Nom dePlume, Ph.D. Why, yes, in fact, I am a rocket scientist. Guide to Medications for Mental Illness: http://www.geocities.com/nomdeplume1000/ =====
From: John on 4 Jan 2006 19:18 >> Hi, >> >> For most anti-depressants (AD:s) a time frame of about 2-5 weeks is > claimed >> for the AD to show it's full effect. But according to several > theories, AD:s >> are supposed to work by indirectly altering the amount of brain > growth >> factors such as BDNF (Brain Derived Neurotrophic Factor), thereby > causing >> re-growth of the parts of the brain that have "shrunk" due to > depression. If >> this is true, then wouldn't the full effect of an AD take several > months or >> more to show it's full effect? After all, if depression has caused > certain >> parts of the brain to "shrink", wouldn't it take more than 2-5 weeks > for an >> AD to cause full re-growth of the brain to a pre-depression state? > > Antidepressants that increase *serotonin* (specifically) seem to > promote new growth of both serotonin receptors and neurons. The time > scale for receptor growth is about two weeks, and for most people, > this correlates fairly well with the onset of mood improvement. That's > not to say that further improvement won't happen in the following > weeks, but the *onset* of improvement usually happens around the two > week mark, giver or take a bit. I suspect (but don't believe anyone > has demonstrated) that persistence of the new growth is what allows > some people to retain the antidepressant benefits after stopping the > antidepressant. > > Increases on the concentration of other neurotransmitters (i.e., > norepinephrine, dopamine, GABA) seems to be felt very quickly, within > hours to days, which suggests that it is simply the increase in > concentration that produces the effect, not new receptor growth. If > so, then stopping the medication should stop the benefits, which is > indeed what I've observed. > Thanks for your response. You say that the onset of brain nerve/receptor regrowth is about two weeks for SSRI:s. But how long does it take for the regrowth to complete, i.e. for the brain to return to a pre-depression state? From what I've heard, the full effect of an SSRI should normally be felt within 4-5 weeks. After that things will not continue to improve, and if you haven't felt relief from your symptoms by then you might as well quit the SSRI. But can full regrowth to a pre-depression state really occur that quickly? Intuitively I would think it should take at least several months, or even years for full regrowth. If that is the case, does this mean that you should you stick with an SSRI for e.g. 6-12 months or more before giving up on it?
From: Larry Hoover on 4 Jan 2006 19:31 "John" <nospam(a)no.where> wrote in message news:43bc6459$0$28922$6d36acad(a)roc.nntpserver.com... > > Thanks for your response. You say that the onset of brain nerve/receptor regrowth > is about two weeks for SSRI:s. But how long does it take for the regrowth to > complete, i.e. for the brain to return to a pre-depression state? From what I've > heard, the full effect of an SSRI should normally be felt within 4-5 weeks. After > that things will not continue to improve, and if you haven't felt relief from your > symptoms by then you might as well quit the SSRI. But can full regrowth to a > pre-depression state really occur that quickly? Intuitively I would think it > should take at least several months, or even years for full regrowth. If that is > the case, does this mean that you should you stick with an SSRI for e.g. 6-12 > months or more before giving up on it? John, there is no evidence that the brain recovers to its pre-depression state, under any circumstances. Very sensitive scans of brain structure have shown that antidepressants are an incomplete treatment for depression. The disease itself continues, despite treatment. There is a very good argument that any treatment leading to remission is of benefit, but the evidence suggests that even the best treatment only reduces the net damage. In full remission, a once-depressed brain is still clearly not a normal brain. I posted a really excellent article on that subject some time ago. I'll see if I can find it. Lar
From: Larry Hoover on 4 Jan 2006 19:48
"Larry Hoover" <larryhoover(a)sympatico.ca> wrote in message news:179f6$43bc68d9$d8a87c43$9527(a)NEXICOM.NET... > > John, there is no evidence that the brain recovers to its pre-depression state, > under any circumstances. Very sensitive scans of brain structure have shown that > antidepressants are an incomplete treatment for depression. The disease itself > continues, despite treatment. There is a very good argument that any treatment > leading to remission is of benefit, but the evidence suggests that even the best > treatment only reduces the net damage. In full remission, a once-depressed brain > is still clearly not a normal brain. > > I posted a really excellent article on that subject some time ago. I'll see if I > can find it. > > Lar Here's the article. http://www.science.mcmaster.ca/Psychology/psych3l03/ReviewPapers/antidpressant.pet.pdf |