A few important things to consider:<p>Lumping all of the medications in question into a single study is disingenuous, and seems biased towards concluding their ineffectiveness.<p>All three of the drugs in question have different mechanisms of action, which means that they will have a different effect on people with different brain chemistry. My read here is that if everyone takes all three and a placebo, performance may be enhanced in one case, but the remaining three cases can make the study come across as conclusive that on the whole, this course of treatment is ineffective.<p>Not a lot of detail on the placebo and why it performs so much better, but I'm curious about the "nocebo" effect and subjects' prior exposure to the non-placebo dosage. In other words, is the feeling of being on a new "smart" drug too distracting to successfully take the test in question for the first time?<p>The sample size is incredibly small at only 40 people, and skewed in terms of population. These were self-selecting individuals who responded to campus advertisements. This has been the modern critique of psychological experimentation in academia for decades, and I find it a little disparaging that we still have to suffer through it. I wish the HRB would ban things like campus advertisements as a means of recruiting test subjects -- we all really ought to know better by now.<p>While the sequencing of studies on each individual helps to avoid some amount of sequence-based confounding variables, and the spacing of seven days between studies allows for a pretty decent return to homeostasis, the number of study participants is still too low to be conclusive. I'd need to see this study get repeated numerous times, at a larger scale, over individuals with a more consistent neurological history to be considered conclusive.<p>I don't entirely buy the efficacy of working on individuals without any history of psychotropic medication or illicit drug use -- remember that this will rule out participants who have taken things like fluoxetine -- ruling out nearly 20% of adults in many countries -- or slightly skirted Australia's drug laws. These are people answering an ad on a college campus, likely for compensation. I don't think it's likely that all the subjects truthfully self-reported.<p>If anything I'd expect the neurological variability of a fully unscreened or undiagnosed population to make it really truly hard to measure these drugs effectiveness. Given the mechanisms of action, I'd expect that the likely 20% of subjects with undiagnosed depression and additional likely 5% of individuals with undiagnosed ADHD would really throw a wrench in any conclusive numbers.<p>I'm not trying to say that smart drugs are the answer to performing better at work. In fact, I'd expect a good night of sleep to make a bigger bump in these kinds of test scores. But I found the BPS is really jumping to conclusions based on what looks to me like very flimsy evidence.<p>Testing on people is hard, but publishing summaries of articles that don't entirely stand on their own and drawing authoritative conclusions is incredibly easy.