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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 6 of 6. This is the beginning of the thread.
Posted by law663 on January 7, 2006, at 23:11:42
I have a question: Depression is associated with cognitive impairment. AD's supposedly relieve this. Yet I have also read that AD's are associated with cognitive impairment.
1. How can this be?
2. What parts of cognition (attention, memory) are involved?
3. What bio pathways are involved?Thanks
Posted by linkadge on January 8, 2006, at 8:32:36
In reply to Cognition, Depression, and AD's, posted by law663 on January 7, 2006, at 23:11:42
Depression itself probably causes memory impairment via a combination of structural and biochemical abnormailites.
There have been some patterns of brain atrophy noted in patients with family histories of depression. Generally glial reductions in the frontal cortex, general grey matter reductions, and of course hippocampal volume loss.
Peturbations of monoamine function may affect memory, attention, and drive.
Many antidepressants tend to work by functionally supressing cholinergic function.Even when the drug is not a direct anticholinergic, like say effexor, it may have
a net anticholinergic effect, by boosting noradrenaline.There are other theories too. SSRI's may supress or dampen certain dopaminergic pathways, which is critical for functional cognition. SSRI's can often reduce dopamine and noradrenaline in the frontal cortex, with the exception of perhaps fluoxetine. The net result may be executive dysfunction.
As well, agonism at certain serotonin receptors facilitates memory, and agonism at others seem to supress it, so taking a drug that acts as an agonist to all serotonin receptors can have a mixed effect on cognition.
On SSRI's I generally experienced reduced ability to concentrate for extended periods of time, as well as a general sort of brain fog where most ideas were harder to grasp.
Linkadge
Posted by law663 on January 8, 2006, at 17:43:13
In reply to Re: Cognition, Depression, and AD's, posted by linkadge on January 8, 2006, at 8:32:36
Why is Prozac different?
> Depression itself probably causes memory impairment via a combination of structural and biochemical abnormailites.
>
> There have been some patterns of brain atrophy noted in patients with family histories of depression. Generally glial reductions in the frontal cortex, general grey matter reductions, and of course hippocampal volume loss.
>
> Peturbations of monoamine function may affect memory, attention, and drive.
>
>
> Many antidepressants tend to work by functionally supressing cholinergic function.
>
> Even when the drug is not a direct anticholinergic, like say effexor, it may have
> a net anticholinergic effect, by boosting noradrenaline.
>
> There are other theories too. SSRI's may supress or dampen certain dopaminergic pathways, which is critical for functional cognition. SSRI's can often reduce dopamine and noradrenaline in the frontal cortex, with the exception of perhaps fluoxetine. The net result may be executive dysfunction.
>
> As well, agonism at certain serotonin receptors facilitates memory, and agonism at others seem to supress it, so taking a drug that acts as an agonist to all serotonin receptors can have a mixed effect on cognition.
>
> On SSRI's I generally experienced reduced ability to concentrate for extended periods of time, as well as a general sort of brain fog where most ideas were harder to grasp.
>
>
> Linkadge
>
>
>
>
Posted by linkadge on January 8, 2006, at 18:20:43
In reply to Re: Cognition, Depression, and AD's, posted by law663 on January 8, 2006, at 17:43:13
Prozac has some interesting properties. In addition to being a serotonin uptake inhibitor, it also blocks the 5-ht2c receptor.
The 5-ht2 system seems to assert an inhibitory controll over frontal cortex catecholamine output.
This may proove to be usefull in some circumstances.
Some more info at:
http://biopsychiatry.com/fluoxdopnor.htm
Linkadge
Posted by Phillipa on January 8, 2006, at 18:39:39
In reply to Re: Cognition, Depression, and AD's, posted by linkadge on January 8, 2006, at 18:20:43
Thanks Link, Fondly, Phillipa
Posted by law663 on January 9, 2006, at 7:38:27
In reply to Re: Cognition, Depression, and AD's, posted by linkadge on January 8, 2006, at 18:20:43
Interesting! Thanks :)
> Prozac has some interesting properties. In addition to being a serotonin uptake inhibitor, it also blocks the 5-ht2c receptor.
>
> The 5-ht2 system seems to assert an inhibitory controll over frontal cortex catecholamine output.
>
> This may proove to be usefull in some circumstances.
>
> Some more info at:
>
> http://biopsychiatry.com/fluoxdopnor.htm
>
> Linkadge
>
>
This is the end of the thread.
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