The high IQ is a bit of a miss—it covers the spectrum, although it is certainly true that there was a tendency for high-functioning people from relatively affluent backgrounds to find their way into a recovery setting years ago. Self-selection was certainly part of it, but we have to keep in mind that more effort would generally be put into "salvaging" somebody who had displayed a lot of promise once than someone who would be a lot easier to write off.

The despair, though, isn't far off: chronic depression, or dysthymia, is common among alcohlics.

The causality of that is highly suspect.

That sounds like an urban legend.