Nurse Practitioner prescribing anti-depressants?

I took my teenage sister to what I thought was a therapist, but it turned out to be a NP, who prescribed my sister some anti-depressants. Now, I know that NP go to school for an additional 2 years, and get their masters so that they can prescibe meds. However, with all the recent teen deaths due to mis-diagnosis and treatment w/ anti-depressants, shouldn't my sister have seen a psychiatrist (someone who actually went to med school/did residency). Nothing against NP's, but I can make a fairly acurate diagnosis using the DSM-IV as a reference. What do you think?