system
Given the following post, respond as if you're commenting on Reddit:
human
Do overall suicide rates decline when methods are made unavailable? E.g., do areas with low firearm ownership have lower overall suicide rates, or do people just try other methods?

I've heard that in the 60s the UK switched from one type of gas for stoves (which had carbon monoxide in it) to another (which didn't), and thus people were no longer able to asphyxiate themselves with carbon monoxide. It apparently led to an overall reduction in suicide rates, the explanation being that suicidal people don't easily take the final step to try to kill themselves, and if there's no convenient method, often suicidal urge passes before they can find a way to follow through.

I also read (from a non-scientific source; just a news story) that something similar happened in Sri Lanka when pesticides were switched so they were less dangerous for humans. This is the same logic with putting barricades or nets that make it harder to jump off bridges.

But is this true? Or is it just correlation, not causation?
gpt
Areas with lower firearm ownership rates have lower rates of *successful* suicides - other methods are less sure.

There was also a law passed in the UK in the '90s that required acetaminophen  (Tylenol) to be packaged in blister packs and prohibited bottles of loose pills.  Over the next several years (presumably as people's medicine cabinets changed out to the new packaging) both overall suicide rates (all methods) and liver failure cases due to accidental acetaminophen overdose declined significantly.

It is damnably difficult to prove causation (instead of mere correlation) in these kinds of studies - there are such large numbers of confounding factors they can't completely be ruled out - but the evidence is at least highly suggestive that suicide method barriers (even something as small as popping pills out of blister packs) cause real reductions in the rates.