Deaths of despair?

In my last couple of posts, I've looked at how people with and without college degrees feel about their lives.  People without college degrees have become relatively less happy with their financial situation, but there's no evidence of a general sense of despair.  But what about the rise of "deaths of despair," which appears to have been mostly among people without college degrees?  I found that the Social Capital Project of Senator Mike Lee has compiled data on historical changes in what are called "deaths of despair" (suicide, alcohol, and drugs), which I use here.   The data go back to 1900, but I just use the years since 1948, so that I don't have to consider the effects of Prohibition, the Depression, and World War II.  Suicide and alcohol-related deaths:

They follow a similar course:  rising until about 1970, then declining until the late 1990s, then rising again. 
 
Now add drug related deaths:

 They follow a different trend:  basically just upward.  For the first part of the period, they were substantially less common than suicide or alcohol related deaths.  They passed alcohol in about 2000, and suicide in 2015--by 2017 (the last year in the data) they were about 50% more common than suicide and twice as common as alcohol-related deaths.

    So drug deaths don't follow the same course as the others.  If you look at them on a logarithmic scale, it's almost a straight line--that is, a steady rate of increase--and if you regress the log of drug deaths on a time trend, adding suicides and alcohol-related deaths doesn't significantly improve the fit.  That is, the three kinds of death don't act as if they are all indicators of the same thing.  

The Social Capital Project report also looks at survey indicators of unhappiness and finds some evidence of a rise since 2000, but it's not very clear. It concludes that drug deaths are different: "apart from the question of whether or why despair may be on the rise, we clearly remain within the grip of a national opioid crisis that requires the attention of policymakers."  As far as why drug deaths would be increasing so steadily, the most plausible answer is technological "progress":  people keep thinking of ways to provide them in more convenient and powerful (and therefore dangerous) forms.