There's no such thing as a free lunch, least of all when it comes to the brain. Particularly troublesome with modafinil is that nobody seems to know how it work

There's no such thing as a free lunch, least of all when it comes to the brain. Particularly troublesome with modafinil is that nobody seems to know how it works, or at least not precisely. We know it's a stimulant of some sort. It appears to act as a dopamine reuptake inhibitor. It increases alertness and resting heart rate. It offers some (temporary) cognitive performance boosts. And it can really help out in a pinch when the user is sleep deprived. The side effects seem a lot more modest and acceptable than those of the amphetamine family, or of Ritalin. Then there's all we don't know. According to the official literature, for instance, modafinil users do not develop a tolerance to the drug. Unofficially, many users complain of an attenuation of the drug's effectiveness with regular use. Either this 'tolerance' is psychosomatic, or the brain is regulating itself as it would with almost any other dopaminergic drug. And what are the long-term consequences of using modafinil, either daily or weekly or monthly? We're not really sure. Longitudinal studies are sparse to nonexistent.