Advertisers frequently trade on the implicit trust we have in medical professionals to sell products for their clients. For example, an advertisement promoting the consumption of 5-Hour Energy has recently been running on television.
The riskier the drug, the more pharmaceutical companies will allocate to its marketing, in order to boost sales of the drug.
Occasional, situational sadness is not pathology -- it is part and parcel of the human condition. Beware of those who attempt to make money by convincing you otherwise.