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David Baxter

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Antidepressants May Work More Quickly Than Thought
November 22, 2006
By Jeff Minerd, MedPage Today

NEW ORLEANS, Nov. 22 -- Research has challenged the conventional wisdom that depressed patients need three to four weeks to respond to antidepressant medication and that any earlier response is due to the placebo effect, said an investigator here.

Measurable non-placebo responses may occur during the first week of treatment, studies published last year suggest, said Ronald W. Pies, M.D., of the Tufts New England Medical Center in Boston, at the U.S. Psychiatric & Mental Health Congress here.

Previous studies, some published in the 1980s, found that while a placebo response was evident at week one and continued unabated, a true drug response did not appear until at least week three. Almost no drug-placebo separation occurred before three weeks, Dr. Pies said.

However, more-recent research has uncovered a different pattern. One meta-analysis published last year included 47 double-blind trials of antidepressants. The trials included more than 5,000 patients on active drug and more than 3,000 patients on placebo. Drugs used included selective-serotonin reuptake inhibitors (SSRIs), tricyclics, and heterocyclics, Dr. Pies said.

This meta-analysis found that 57% of the drug-placebo separation occurred during the first two weeks of treatment. The magnitude of improvement in symptoms diminished after two weeks in both the active treatment and placebo patients, Dr. Pies said.

Other studies published in 2005 found that the best predictor of long-term response to antidepressant drugs was in fact the degree of symptom improvement during the first two weeks, Dr. Pies said.

These findings raise the question of whether physicians should be switching antidepressant drugs sooner, rather than having patients bear the cost of four to six weeks on a drug that isn't working after the first two weeks, Dr. Pies said.

However, Dr. Pies said, the newer data does not exclude the possibility that the full drug benefit might take longer to emerge -- perhaps three to 10 weeks.

In addition, although the meta-analysis found statistically significant improvements in depressive symptoms, these may not translate to robust, clinically significant changes in the real world, Dr. Pies said.

Furthermore, some symptoms of depression may improve quickly with treatment while others take longer. For example, guilt and anxiety may improve during the first week of treatment, but libido and insomnia might not improve until nine weeks of treatment, Dr. Pies said.

"Therefore, waiting three to four weeks to asses a patient's response to an antidepressant is still reasonable," Dr. Pies said.

However, a patient reporting symptom improvement extremely early -- within two to 48 hours of treatment-is likely to be experiencing a placebo response, he said.

And it is important to realize that comprehensive recovery from depression takes time -- perhaps four or more months, Dr. Pies said.
 

foghlaim

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drug-placebo separation, don't understand what this actually means.

also how does a patient respond to a placebo if in fact the pacebo is a dud pill? can never understand this aspect of trials either. does it mean that the patient who is taking the placebo thinks they are taking the real thing and get better just because they believe they are taking the real thing?
i don't understand this really.. especially for instance.. when talking about depression.. if depression is a chemical imbalance and needs meds to get corrected, how does a placebo appear to get similar response. ??
 

ThatLady

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The mind can do amazing things, Fog. When given a placebo, a person who is easily influenced, and who believes they are getting a healing medication, may experience a perceived reduction in negative symptoms. That's called a placebo effect.

The experience is caused by the patient's belief that the "medication" is helping them. Usually, however, the placebo effect is short-lived. The symptoms return because no real treatment is being received, and once the "new" wears off, the patient returns to the pre-trial symptomology.
 

foghlaim

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"and once the "new" wears off, the patient returns to the pre-trial symptomology."
is this what is meant by drug-placebo seperation then,?
as in the person on the real drug continues to improve or gets stabilised.. (whichever applies here) and the poor sod on the dud goes back to be unwell? Like both goes their seperate ways as it were.
 

ThatLady

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Yes. That's pretty much what happens. It's the only way to determine for sure if a drug actually works. Those who are on the placebos don't get the benefits of the medication, if it's found to work. However, they also don't get the negative effects of those medications that are found not to work, or to produce nasty side-effects. It's a trade-off, I guess.

I'm pretty sure that, in many of these trials, when and if the medication is found to be efficacious, it is offered to those who participated by taking the placebo, as well. :)
 

foghlaim

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"I'm pretty sure that, in many of these trials, when and if the medication is found to be efficacious, it is offered to those who participated by taking the placebo, as well. :)"

I would hope so... given the poor sod on the dud was hoping for some improvement and hopefully for free as well, given they were taking part in a trial.
Thanks TL. tis a fair bit clearer for me now..
 

David Baxter

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I would hope so... given the poor sod on the dud was hoping for some improvement and hopefully for free as well, given they were taking part in a trial.
In these studies, participants are informed that some of them may be recieving a placebo, so they are aware that there are two groups - just not which group they've been assigned to. In most cases, even the people gathering the data don't know which group the individual is in until the study is completed (so-called "double blind" procedure).
 

Retired

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I cannot recall the data at this time, but perhaps David does. In typical studies involving anti depressant medications, placebos are reported as having remarkable effectiveness.

This is not to diminish the value of actual medications, because over the long term the alteration in brain chemistry appears to have therapeutic effectiveness.

The point is, as has been stated, the mind can sometimes be influenced in surprising ways.
 

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