Well, in terms of driving, talking on a hands free phone might be worse for your driving than being over the limit[0]. And that's from pure addiction and distraction; there are no exogenous chemicals physically altering you.

[0] https://www.trl.co.uk/uploads/trl/documents/TRL547.pdf

> national safety organizations estimate that cell phone use is a factor in approximately 23% of all car accidents, contributing to millions of crashes nationwide

U.S. Government info: https://www.nhtsa.gov/risky-driving/distracted-driving