Are the drugs prescribed for the person? Are the drugs obtained legally?

As a general rule, no, if you overdose or take drugs you do not need and they are prescribed for you and obtained legally, no, you cannot.

You can, of course, be arrested for driving under the influence of drugs, prescription or non-prescription.

What are the circumstances?

It is a criminal offence to abuse prescription drugs to the point where you falsify prescriptions for controlled substances. If they are your own prescription drugs, then I don't know how you would be caught unless you were stealing them.

Tick