How?

Oscar-winning actor Heath Ledger died at age 28 from an accidental prescription drug overdose in January 2008.

How does one accidentally overdose on prescription medication? The directions are on the label. If one takes as directed then one is okay. If one takes more than is prescribed then one can die. Either one has to do this on purpose or one has to be forced to do this. It can't be an accident.

If a person is taking precription medication that has not been precribed to them and they die, isn't that still taking medication on purpose?

So I am thinking that "accidental overdose" is just a code for "he screwed up big time".