Posted by Cam W. on May 27, 2000, at 1:06:17
In reply to Re: Information - Elizabeth, posted by SLS on May 26, 2000, at 8:06:25
Scott - I have been bonig up on my geriatric psychopharmacology lately. Here is some of what I remember from what I have read.
> Is there a greater occurrence of melancholic or psychotic depression in the elderly?
Not really. Many depressions in the elderly are drug-induced (eg corticosteroids, NSAIDs, phenothiazines) or disorder-induced major depressive disorders (Parkinsonism, Alzheimer's, chronic bronchitis). Many depressions in geriatric patients are missed because many of the symptoms of depression are also thought to be results of aging. Ten percent of late-onset depressions (depression in the elderly) have comorbid severe cognitive impairment, though. Seventy percent of elderly depressed patients have measureable cognitive deficits, which can affect their quality of life. Cognitive impairment increases normally with age, further with depression and still further with the exacerbating effects of many centrally active drugs, including antidepressants.
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> I am pretty sure that tricyclics tend to be more effective in the elderly. Is this true?No. Several studies have demonstrated that TCAs produce impairment in cognitive and psychomotor function that is not just due to sedation. The TCAs have very potent antihistaminic effects (histamine release facilitates cerebral arousal through it's interaction with postsynaptic H1 receptors which is block by antihistaminergic action). TCAs also have very potent anticholinergic effects (the cholinergic system is also involved in the maintenance of arousal and more specifically, in the encoding, immediate active processing and storage of information - ie working memory, it's transferral to long term memory and memory retrieval ; anticholinergic effects block this).
Both of these effects can cause psychomotor impairment by retarding the flow of sensoimotor information (esp. during activities requiring continuous manual control - eg driving a car). Tolerance does develop to the sedation and psychomotor impairment caused by TCAs, but not to memory disturbances. Therefore, TCAs should not be used in the elderly, if at all possible.
Paxil, while used extensively in the geriatric population, may also not be a good choice. It has anticholinergic effects and may decrease dopamine neurotransmission (via sertonergic mechanisms) in the prefrontal cortex, leading to cognitive related deficits. Zoloft or Celexa may be a better choice in the elderly (although, because Celexa is a purer SRI, it may also cause some hypodopaminergic related cognitive deficits). Zoloft enhance PFC dopaminergic function to a certain extent.
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> Do you think pseudodementia is being more properly diagnosed as depression now as compared to ten years ago?Sorry, don't know. I'm a terrible diagnostician.
poster:Cam W.
thread:32651
URL: http://www.dr-bob.org/babble/20000526/msgs/34819.html