Presumably, this discrepancy reflects different methods of suicide in the two countries (eg. more frequent use of firearms, hanging, and suffocation in Canada versus poisoning in the UK)[29,30].
That’s probably the crux of it. If firearms were readily available in the UK I expect you’d see a marked fall-off in the incidence of intentional suicides via over-the-counter drugs. (Quick, legalise guns!!)
I wonder if part if it is cultural / ignorance too; it’s maybe perceived as an “easy” way to off yourself, pop a few pills, go to sleep and don’t wake up.
Probably common in “cry for help / attention” suicide attempts too, the thinking being that you can take a few tablets and then be taken to hospital where they’ll all go “there there” and sort you out.
I’d bet that a large percentage of people taking intentional overdoses don’t have the remotest idea about the reality of the implications.