Comment by jychang

The problem is that these studies are narrow and only look at a handful of the aspects of consumption.

http://en.wikipedia.org/wiki/Health_effects_of_caffeine

> Short term side effects such as headache, nausea, and anxiety have been shown as symptoms of mild caffeine consumption.

When assessing the health impact of a drug, it is important to look at the whole picture.

Amp is indeed neurotoxic, though the exact effect is a little nuanced and dose-dependent.

http://www.ncbi.nlm.nih.gov/pubmed/15019431

> In addition to the social, cultural and indirect medical complications of amphetamine analog abuse, this class of drugs is also known to have the potential to damage brain monoaminergic cells directly.

http://www.ncbi.nlm.nih.gov/pubmed/17606768

> In early studies, high doses of amphetamine, comparable to amounts used by addicts, were shown to damage dopaminergic pathways. More recent studies, using therapeutic regimens, appear contradictory. One paradigm shows significant decreases in striatal dopamine and transporter density after oral administration of "therapeutic" doses in primates. Another shows morphological evidence of "trophic" dendritic growth in the brains of adult and juvenile rats given systemic injections mimicking "therapeutic" treatment. Imaging studies of ADHD-diagnosed individuals show an increase in striatal dopamine transporter availability that may be reduced by methylphenidate treatment.

I did not claim that caffeine and modafinil are neurotoxic, just amphetamine.

You do however build up a tolerance to modafinil, and it has various negative side-effects. But I agree that it's weird to make some sort of hard separation between various types of nootropics, and say that you should never touch some. Everything potentially has its use, and I think that Gwern covers this topic exceedingly well at his site.