The antidepressant debate

Publisher Website
Google Scholar
Abstract
The issue of ‘unblinding’ or the ‘amplified placebo effect’ (Thomson, 1982) has been raised periodically since the 1960s. The suggestion is that a whole or part of the superiority shown by antidepressants over placebo is attributable to the non-specific effects of taking an active medication as opposed to an inert one, in a context in which there are usually high expectations of active treatment. Greenberg et al (1994) showed that effect size correlated with incidence of side-effects in trials of fluoxetine. They also found that the effects of older antidepressants compared with placebo were less than the effects of newer ones in a meta-analysis of three-arm trials comparing a new antidepressant and an old one with placebo (Greenberg et al, 1992). They suggested that this was due to reduced expectations of the performance of the older antidepressants. Moncrieff et al (1998) found lower effect sizes in trials using active placebos. Quitkin et al (2000) challenged the importance of ‘unblinding’. They failed to replicate the findings of the meta-analysis of three-arm trials using categorical outcomes rather than continuous ones. However, use of categorical outcomes may in itself inflate drug—placebo differences (Moncrieff, 2001). Quitkin et al also criticised the findings from active placebo-controlled trials on the basis that drug improvement rates were lower than expected.

This publication has 25 references indexed in Scilit: