Moreover, Robert Emmons, perhaps the world's leading scientific expert on gratitude explains in his article "Pay It Forward" why Americans typically underestimate the importance of gratitude, and discusses surprising and encouraging results that he's uncovered, outlining gratitude's positive impact on people's emotional, social, and physical health.

These articles provide readers with solutions to obtain happiness.

The Emmons article can be found at:
http://greatergood.berkeley.edu/greatergood/current_issue/emmons.html

and the Alberts artilce:http://greatergood.berkeley.edu/greatergood/current_issue/alberts.html

(a) The authors aren't necessarily suggesting people are going on and off anti-depressants. Rather, for some people, July is the straw that broke the camel's back.

(b) Yes, I think this is a bit of a problem. The authors don't really address this solidly. Following on from (a) though if you buy the 'straw' theory perhaps it's more plausible.

Here's a quote on that covers these two points:

"...the people who were likely to cause increases in our DDD measure were those who were already receiving treatment for depression (and who needed increases in doses) or those who were depressed and need something to tip them over the edge to get diagnosed and treated. The Swedish medical system allows relatively easy access to primary care, so the lag between when an individual wants to consult a physician and dispensation of the prescribed drug need not be long. Lags of some weeks duration would be captured with our monthly DDD and temperature data as analyzed here, but longer lags would not." (Hartig et al., p. 114).

The vacation theory is a good alternative explanation - and one the authors consider. Hartig et al. argue people on anti-depressants planning a holiday will have stocked up well before they go away on vacation.

The other alternative the authors mention which I like is that people are depressed because their kids are home from school and stuck inside as the weather is bad! But, Hartig et al. argue, parents might not face any greater stress because their kids are stuck in the house than if they can roam free. Also, what percentage of the sample have children? We don't know.

My understanding of anti-depressants is that:

a) once you are on them, you stay on them. An on-off-on-off regimen of antidepressants is quite dangerous, and;

b) there is a lag time between the time one experiences clinical depression, when one is diagnosed with clinical depression, and when antidepressants actually start kicking in.

To suggest that all that happens in the time span of 30 days seems a stretch.

Without having read the study, the first alternative explanation that comes to mind is that fewer prescriptions were filled in July because when the weather was warmer because they were more likely to be on vacation, and away from their physician...

Just a wild guess... I'll have to check it out when I have some free time.