I am a software engineer by trade and have done some work on the neural network types of AI used to do things like this (although I used them to help big tech target you with ads). They are not talking about a breathalyzer machine - you need eye tracking sensors, sweat sensors, body position sensors. It literally uses your entire biometric data in real-time as its input. These systems are pretty good but not 100% accurate, and are extremely invasive.