previous post, I have gone on about the errors about the treatment of depression in the latest blog entry on the APA's Healthy Minds. Health Lives. There's another mistake about how long it takes for antidepressants to work. Patients are commonly told, as they are in the blog entry, that antidepressants can take up to 4 to 6 weeks to have an effect.
What the blogger should have said is that it commonly takes 4-6 weeks for a statistically significant difference between active and placebo treatment to be detected in clinical trials. But this is an artefact of the way in which statistical significance is measured. Larger size clinical trials will detect a statistical difference earlier than trials with smaller numbers of subjects.
Actually, the largest improvement per unit time produced by antidepressants occurs within the first 2 weeks of treatment (Mitchell, 2006). Recovery from depression fits an exponential model (Priest et al, 1996). The false 'delay' hypothesis has been used to call for research into better antidepressants that act more quickly. Maybe it would be better just to be honest and accurate with patients about the limitations of antidepressants.