i-Dosing is the use of auditory tones in an attempt to alter consciousness in ways that mimic recreational drugs. The technique involves playing two different tones simultaneously to produce a perceived tone inside the head, in order to alter brainwaves.
Although i-dosing is popular, and has been portrayed on online videos, it is unclear whether the effects are placebo, exaggerated, staged, or genuine. It is possible to therapeutically alter brainwaves through the use of techniques such as neurotherapy, although the effects of this are typically experienced as subtle improvements in functioning rather than a "high" that might be experienced with cocaine or marijuana. Clearly, there are no toxicity issues in i-dosing.
In the same way that it appears to be possible to become addicted to video games and other forms of media, it is theoretically possible to become addicted to i-dosing -- just as it is theoretically possible to become addicted to food or sex. However, there is a lot more to addiction than one-time or occasional engagement in the activity.