The article refers to some form of clinical depression. Having the blues is not depression. Although we dont know the exact correlates of depression, we know

The article refers to some form of clinical depression. Having the blues is not depression. Although we dont know the exact correlates of depression, we know it has something to do with neurotransmitters and is most definately physiological (note how hormonal changes such as birth can cause depression, or how SSRIs are used to treat depression). It's the denial of this fact that usually leads to drug aversion.