What Does Happiness Cost?

Two dollars and seventy-six cents per day:

[...] Moreover, they add that the combination of low incremental costs and a high clinical benefit in terms of depression-free days resulted in "the lowest incremental outpatient cost per depression-free day that has been reported in primary care trials: approximately $2.76 per depression-free day." [...]

In fact, though, happiness is not the same as being depression-free.  Merely eliminating depression does not necessarily make a person happy, any more than eliminating tuberculosis makes a person happy.  

To illustrate: imagine a person with tuberculosis, who just had his home, family, and means of livelihood wiped out by a tsunami.  Some folks from the UN come by and cure his tuberculosis.  He's still not happy.    In contrast, imagine someone with sleep and appetite disturbances, low energy, impaired concentration, anhedonia, who has a wonderful family, a decent home, and a good job.  Take away the symptoms; that person will be happy.  Well, probably.