Placebo active

For example, if two treatments (a phytochemical product vs a placebo) are being evaluated to assess the influence of the active product on blood pressure, half of the subjects might be in the active-placebo sequence and the other half in the placebo-active sequence. If the active product lowered blood pressure and the effect continued after the treatment was stopped, then blood pressure might be lower during the placebo period for subjects in the active-placebo sequence than would be the case for those in the placebo-active sequence. This might be detected as a lower level of blood pressure before the start of the second treatment among subjects in the active-placebo treatment. 

O Instead of using a DATA NULL step as was done in Program 5.4, this program uses PROC SQL to define the three macro variables, nl, n2, and n3, that are used in the column headings for Active, Placebo and Overall therapy groups. The macro variables also serve as denominators to be used for percentage calculations. 

What would happen if active placebos were used in clinical trials, rather than inactive placebos Would one still get the relatively small but significant difference between drug and placebo We already have the beginning of an answer to this question. 

When antidepressants are compared to active placebos, differences in outcome are substantially harder to find. 

Although the tailoring hypothesis does not fit the data, there is another hypothesis that works just fine. It is the idea that antidepressants are active placebos. That is, they are active drugs, complete with chemically induced side effects, but their therapeutic effects are based on the placebo effect rather than their chemical composition. Their small advantage in clinical trials derives from the production of side effects, which leads patients to realize that they have been given the active drug, thereby increasing their expectancy for improvement. 

S. Wessely and R. Hardy, Active Placebos Versus Antidepressants... 

Table 4.4 Active/pLacebo comparison, binary outcome survival (hypothetical)...

CT plus active placebo (atropine and phenobarbitone in very small doses to imitate the concomitant effects of the antidepressant)... 

AU = allergenic units RU = rast units. Active/placebo. 

Moncrieff, J., Wessely, S., ffardy, R. 1998, Meta-analysis of trials comparing antidepressants with active placebos, Br.J.Psychiatry, vol. 172, pp. 227-231. 

Subject number Weight after placebo (kg) Weight after active (kg) Change in weight (active-placebo) (kg)... 

Working memory easy task Placebo, then 0.26 mg/kg, IV 0.65 mg/ kg/ 100 min plus active/ placebo LY354740 (100 mg, 400 mg)... 

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