Even if just 11% of American adults are currently on antidepressants, you have to consider that those are not evenly distributed across the population. Those 11% are going to be concentrated among those who have insurance and access to health care, can afford co-payments for medication, have doctors who favor medical treatment for signs of depression and come from a cultural background that does not stigmatize antidepressants more than normal. Add in the tendency to self-select one’s peers and to discuss personal issues with an even more select group, and I could easily imagine that someone might find that nearly every young person with whom they broach the subject might actually be or have been on antidepressants, even if that person broaches the subject with a lot of people, relatively speaking.
Keep in that some generic antidepressants are not that expensive. I checked and a bunch of them are listed under Samsclub $4 for a 30 day supply. That doesn’t require a membership. I wouldn’t be surprised if a lot of these prescriptions are written under Medicaid. There is also an extremely high percentage of people that are taking antidepressants without being diagnosed with a condition that required it.
http://www.ncbi.nlm.nih.gov/pubmed/21294990
http://i.walmartimages.com/i/if/hmp/fusion/customer_list.pdf