idk about that, one big example was Israel. Back in 2005 they ended the practice of IDF troops taking guns home on weekends, and the suicide rate fell by 40% instantly without them doing anything else.
https://www.ncbi.nlm.nih.gov/pubmed/21034205Regardless of how USA compares internationally, the suicide rate would fall if there weren't guns to do the deed with. They have studies that show a correlation with gun ownership and suicide:
https://en.wikipedia.org/wiki/Gun_violence_in_the_United_States#SuicidesA 1992 case-control study in the New England Journal of Medicine showed an association between estimated household firearm ownership and suicide rates, finding that individuals living in a home where firearms are present are more likely to commit suicide than those individuals who do not own firearms, by a factor of 3 or 4.
As for Japan vs USA, you can look at OECD data such as this:
https://www.oecd.org/els/family/CO_4_4_Teenage-Suicide.pdfSee the chart on page 2 of the pdf. Teen suicide was
higher in the USA in 2015 than in Japan. It was also higher for the data points of 1990 and 2000. e.g. teen suicide rates for the USA have consistently trended higher than Japan for decades, despite what the media tells you. Japan's teen suicide rate in 2015 was actually lower than the OECD average, while America's was higher than the OECD average.
The thing is that in Japan the media makes much more of teen suicides than the USA does, despite it being no better (and arguably worse) in the USA. The reason for the difference in perception is probably because teen suicide used to be
much rarer in Japan, and more common in the USA, e.g. back at the height of the 1990 crack epidemic USA's teen suicide was three times higher than Japan. Now, they're more even so the Japanese are freaking out about it, while the USA is not. The western media just reports Japanese news as a fact without doing much fact-checking. See for example the "Japanese eyeball licking" craze as it was credulously reported in the West (e.g.
CBS), which
turned out to be a hoax.