In 1998, the UK reduced the maximum pack sizes of paracetamol (acetaminophen) tablets. We saw no reduction in the number of people who attempted suicide by paracetamol overdose, but a 43% reduction in deaths by that means.
https://www.bmj.com/content/346/bmj.f403
There is some evidence to suggest that gun control is effective in reducing deaths due to suicide.
https://www.ncbi.nlm.nih.gov/pubmed/26396147 https://www.ncbi.nlm.nih.gov/pubmed/29078268 https://www.ncbi.nlm.nih.gov/pubmed/29852823
Due to the method, we know when she obtained it, and the circumstances around that. She got it when there were suicides in her local community, and in retrospect she had probably been thinking about it at the time. She definitely had some mental health issues at the time centered around overwork. She kept it for years, and finally used it when she had a minor setback at work.
(+ not a gun)
However, I don't see any reporting on how Bourdain died, only that he was found in a hotel room. So unless it comes to light that guns were involved (unlikely, because gunshots would have been heard), I don't think this sad event begs for a discussion of guns as opposed to many other topics around the issue of suicide.
Or you know, there might be a third variable there... Something about declining rural areas possibly.
There's also a lot of theory to back up the idea that guns increase suicide rates.
First, if people have to take time to prep for suicide, they have time to think and sometimes change their minds. With a gun, the time between thought and action is so small, they don't have this chance.
Second, guns have a much higher success rate than most other methods. This is why women attempt suicide at higher rates, but succeed far less often -- they usually don't use guns.
There are studies that look at a stable population, and they find that the same person is much more likely to succeed at suicide after they become a gun owner.