Intoxication is typically voluntary, which is why the authorities come down so hard on drunk drivers. You knew you were drunk, you knew driving would put others in danger, and you chose to do it anyway.
But what if you didn't know you were drunk? What if you actually tried to follow the law, but someone else caused you to break it without your knowledge?
This is sometimes referred to as involuntary intoxication. You didn't make that choice; someone else made it for you.
For example, maybe you went out to dinner with your friends after work. You ate a salad and got a beer. You were there for an hour, so you figured one beer -- especially on top of food -- would mean you were still plenty safe to drive. You shouldn't have been over 0.08 in terms of BAC.
While you were there, though, someone spiked your drink with two shots. You never knew, but you basically had three entire drinks in just under an hour, so your BAC was over 0.08 when the police pulled you over. You had no idea what happened, and you feel the blame should fall on the person who caused you to drink more than you ever wanted to drink.
This term is also sometimes used to refer to spiking a drink with drugs. When this happens, people sometimes claim they can't remember anything after the fact, meaning they were not capable of making prudent choices. They never would have driven had they really understood the danger.
If you're facing charges, especially when you think someone else was really at fault, it's critical to know about all of your legal defense options. Involuntary intoxication does happen, whether as a prank or for malicious reasons, and it can put you and others in danger.
Source: Cornell Law School, "Involuntary intoxication," accessed May 24, 2017