As I noted in another post this device looks like more of a memory and learning aid rather than targeting IQ. My lay hypothesis is that this device works by increasing the baseline of current flow at target synapses - kind of like waking the guard of a gate to a vigilant state. Basically, it enhances long term potentiation. I expect it will have a very low addictive profile and improper use will probably be toxic in a similar mechanism as glutamate overload. No worse than people who consume alchohol regularly do to themselves. Probably much safer. High currents might cause seizures though.