Not necessarily, perhaps just the opposite. Whatever made the person vulnerable (the diathesis part) may still be present. Besides, this research is relatively young.
On Sun, Jul 24, 2011 at 3:54 PM, William Scott <[email protected]> wrote: > > > > > > If this were true, wouldn't we expect depression not to recurr after > termination of a thorough anti-depressant medication treatment? The data > seem to show otherwise. > > Bill Scott > > > >>> Carol DeVolder ** 07/24/11 12:45 PM >>> > > > > > > This is kind of a long post, and many of you will not be interested in it > at all (maybe nobody), but this is in response to the discussion of > antidepressants, depression, its potential causes, and so on. I'm not > turning it in for a grade, so please don't grade me on it. I hope it is > somewhat coherent though, because I really like all of the possibilities for > explanation that emerge in this model. In a previous post, I mentioned > Robert Julien’s *Behavioral Pharmacology* as an excellent resource. Of > course I don’t think he has the final word on the topic of depression and > antidepressants, I do think he provides valuable insight. Paraphrasing what > he has to say on the topic (paraphrasing liberally, I might add, so don’t > fault me for plagiarism—I already know that I am doing that), starting with > the pathophysiology of depression, Julien describes what he refers to as the > neurogenic theory of depression. > > > > This description describes depression as related to loss of volume (due to > neuron loss), especially in the hippocampus. Julien points out that > numerous symptoms of depression such as impaired attention, concentration, > and memory are related to functions of the hippocampus or the prefrontal > cortex. He also notes that chemicals such as cortisol can have deleterious > effects on the functioning of the hippocampus and prefrontal cortex(tying > together the research that suggests that stress can result in loss of brain > volume, especially in these areas). According to research by Frodl et al. > (2007), the hippocampus actually shrinks when exposed to a variety of > stressors, including depression. That same research reports that stress is > one of the most common causes of depression. > > > > However, Julien notes that recent research has shown that existing neurons > are able to repair or remodel themselves (plasticity), and in fact > neurogenesis also is possible; again, especially in the hippocampus, but > also in the prefrontal cortex. According to his explanation, two known > second messenger neurochemicals are important in protecting neurons from > damage due to trauma or injury, and in promoting and maintaining the health > and stability of newly generated neurons. Julien argues that antidepressants > increase the action of these 2nd messenger systems resulting in repair and > restoration of volume to the hippocampus and possibly the prefrontal cortex. > > > > Here’s a stepwise summary of how these 2nd messengers might act in the > presence of SSRIs /SNRIs or other antidepressants: > > > > Step 1: Antidepressant drugs increase the level of the monoamines > (especially 5-HT and NE) in the synapse. > > Step 2: binding of either 5-HT or NE triggers a 2nd messenger system that > uses cAMP (cyclicAMP). > > Step 3: cAMP triggers the expression of CREB (cAMP > response-element-binding protein). > > Step 4: CREB activates the production of BDNF (brain-derived neurotrophic > factor) > > Step 5: BDNF promotes healthy neurons and connections (likely involving > the growth of new neurons, especially in the hippocampus). > > > > Julien supplies ample references to support these statements. Also, Julien > writes that the time frame in which all of these steps occur might explain > the therapeutic lag that accompanies the onset of administration of > antidepressants and the onset of their therapeutic effect. > > > > If you’ve read this far, hopefully I’ve shown the possibility that > depression may be due to stress (loss of a loved one, job loss, ongoing > factors), chemical imbalance (genetic or acquired), or the interaction of > any or all of these factors (the diathesis-stress model). Although > antidepressants may alleviate depression under this model, other things can > as well; for example, psychotherapy, exercise, self-help, stress-reduction > techniques, or time. > > > > Some references: > > Angelucci, F., et al. (2005). BDNF in schizophrenia, depression, and > corresponding animal models. *Molecular Psychiatry* 10, 345-352. > > Blendy, J. A. (2006). The role of CREB in depression and Antidepressant > treatments. *Biological Psychiatry, 59,* 1144-1150. > > > > Duman R. S. and Monteggia, L. M. (2006). A neurotrophic model for > stress-related mood disorders. *Biological Psychiatry, 59* , 1116-1127. > > > > Frodl, T. et al. (2007). Association of the brain-derived neurotrophic > factor Val66Met Polymorphism with reduced hippocampal volumes in major > depression. *Archives of General Psychiatry, 64*, 410-416. > > > > Nair, A., and Vaidya, V. A. (2006). CyclicAMP response element binding > protein and brain-derived neurotrophic factor: Molecules that modulate > our mood? *Journal of Bioscience, 31, *423-434. > > > > Done for the day--going outside as soon as it stops raining. > > Carol > > > > > -- > Carol DeVolder, Ph.D. > Professor of Psychology > St. Ambrose University > 518 West Locust Street > Davenport, Iowa 52803 > 563-333-6482 > > This e-mail is probably not confidential, but please don't share it without > asking. > > > > --- > > You are currently subscribed to tips as: [email protected]. > > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13058.902daf6855267276c83a639cbb25165c&n=T&l=tips&o=11592 > > (It may be necessary to cut and paste the above URL if the line is broken) > > or send a blank email to > leave-11592-13058.902daf6855267276c83a639cbb251...@fsulist.frostburg.edu > > > ** > > --- > > You are currently subscribed to tips as: [email protected]. > > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=177920.a45340211ac7929163a0216244443341&n=T&l=tips&o=11596 > > (It may be necessary to cut and paste the above URL if the line is broken) > > or send a blank email to > leave-11596-177920.a45340211ac7929163a0216244443...@fsulist.frostburg.edu > > > > -- Carol DeVolder, Ph.D. Professor of Psychology St. Ambrose University 518 West Locust Street Davenport, Iowa 52803 563-333-6482 This e-mail might be confidential, so please don't share it. --- You are currently subscribed to tips as: [email protected]. 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