Are medical staff checked out thoroughly

[Hamble]

The mass murderer who topped himself in jail.

You omitted 'addict'.

[said]

You omitted 'addict'.

There has been many reports of medical staff becoming addicts on the drugs they prescribe.

[Hamble]

There has been many reports of medical staff becoming addicts on the drugs they prescribe.

This is the sad thing.
A qualified Dr may be a good and honest practitioner to match the reference/employment checks before a dependence/addiction on controlled drugs.

Crossing the line to fraud to obtain a supply of drugs there is no redemption or end until found out.
Whether by killing others or oneself the end result is tragic.