Only deaths directly caused by a drug should be recorded as a drug-related death.  You definitely want to avoid the ridiculous situation that existed in the US where you could be killed by something totally unrelated, say a satellite falling out of the sky, and that would be recorded as drug-related if you had a drug in your system.

Aren't hallucinogenic drugs and drugs like MDMA that are known to be relatively safe also largely ignored by the Netherlands police?