I wonder what is the difference between the two groups as far as the rate of finding employment. Might be that the act of looking for a job is stressful. If the goal is to get people back to work, it might not make sense to optimize just for better mental health.
I'd like to see welfare systems and tax codes modified with a rule that no situation can cause more than a 50% marginal "tax". (Which would mean many cutoffs in the tax code would effectively be replaced with phaseouts even if Congress didn't specifically fix them.)