One reason why Americans have lost their passion and don't seem to care about very much is that they are taking large quantities of psychotropic drugs, many of which level their moods so that they are not too happy and not too sad.
In 2011 the top 25 psychiatric medication prescriptions numbered a staggering 391 million. Most of these prescriptions are for drugs such as SSRIs, SARIs, SNRIs or NDRIs for depression, anxiety and other mental disorders, with just 33 million of the prescriptions intended solely for attention deficit disorder.
Data here.
