High dose Benzos depress breathing. So they are additive as a risk for mixing with opiods which also depress breathing.

Also Benzos are not safe for the elderly, as renal clearance decreases with age, so they remain in the body longer and if other drugs are present, there is increased likelihood of an interaction there.

Much has to do with dosing levels, age, and kidney functions.

And tolerance to Benzos happens quickly so increasing doses is necessary, and eventually one realizes they are on too much.

One needs to consult a Cytochrome-450 drug/liver metabolism chart to see if there are metabolic interactions or Q-T risks for the heart.

I have read online from interviews with his friends that Prince used opiods and stimulants to
get fired up for performing. If this is true they fueled his performances and was similar to other musicians out there. The group Fleetwood Mac was heavily into drugs and alcohol too by comparison. I saw an interview on TV with Stevie Nicks who stated that Klonopin (Benzo) was far
worse to get off than Cocaine! She said it took her 8 months of agony to do that.