As I mentioned: even if this turns out to be factor – and I'm not sure it even is – then I don't think this accounts for 100% of the increase. I don't profess this is the full explanation, merely a possible factor, out of several.
I'm also reminded by my uncle, who was born with a serious and debilitating heart condition; he always said that if he had listened to his doctors he'd be a "victim" in a wheelchair inside all day. Of course he did need serious medical attention, including a heart transplant, and he did end up dying from his condition at the age of 51, but overall he led a "good life" and just carried on with things without seeing himself as too much of a victim. It probably would have been a different life if he did. Mental feedback loops can be pretty powerful.
It's also worth pointing out the charts look a bit less drastic if you zoom out to the 70s; in fact, suicide for boys especially was a lot higher in the 80s than it is now. The author does address that briefly at the bottom, and provides a link with more detail (which is too much to quote here, but tl;dr is that they believe it's correlated to lead exposure and crime rates – this link also contains the longer timeframe charts).