Mental illness was and (albeit to a lesser degree) is a severe drain on my energy and productivity; I believe that for many this may account for the reduced income levels relative to "comparable peers".
Psychiatric care coming after an attempt may close this gap in productivity, allowing for increased income.
Of course, I speak only of my own experience and cannot of others'.
It may be enlightening to compare changes in income based on the presumed basis for the attempt or ideation (i.e. mental illness, economic circumstances, or familial / social factors).
I believe it to be especially important to study those suffering from mental illness separately, as illness can beget thought processes severely lacking in logic and rationality; an economic model assumes a level of rationality in the decision-making process that may not necessarily be present.
Or maybe they internalised the idea "may as well try this difficult thing, I've tried suicide before so I can do it again" as a kind of backup/escape option that feels more real and available.