You also have a whole lot of criterias that a professional can check if you match into or not. There are serveral tests for mood and emotional level that they can only test by talking with you, clinical signs and symptoms.
One of the tools that mental health professionals have, is called DSM (Diagnostic and Statistical Manual of Mental Disorder), basically a book that gets updated and reviewed.
Along that, it's maybe not as important how severe a deression is, if you can just find the correct way to cope with it, but it is helpful to your doctor to know if it is a clinical depression or a little less severe depression - as in how to determine medications or not.
Florena
I think there are some types of depression (bi-polar) that can actually be measured by bloood tests but you didn't specify testing for a bi-polar disorder. Some drs just seem to assume that if a person is sad, he/she is depressed so they prescribe medication which might not help. A good shrink will talk to the possibily depressed person to ascertain the degree of depression, everything from suicidal to "the blues" and then both the shrink and the patient will decide on a course of action. Depression and anxiety also tend to go together so a good therapist will look for that too. A "good" therapist will want to see you on a consistent basis to see what is best for you and what will work best - meds, talk therapy, etc. Just a suggestion - stay away from any shrink who talks to you for a few minutes, writes you a prescription and does not make a follow up appointment.
Don't know if this helps or not. You are probably the one who can best determine if you are depressed or not. If you've been "sad" or "down" for a number of weeks, you could be depressed. If you've been down for a short time it could just be "the blues".
They check to see if you got your bill yet!
I'm sorry, I'm so sorry, it was just laying there and I had to pick it up. I have no knowledge of these things, with me they just asked a few questions and from the answers deduced I was depressed, had PTDS, am antisocial, and am the sort of idiot that makes jokes in a depression forum.
The questions were pretty obvious, like "have you thought of harming yourself" and "do you think your family would be better off without you" and things like that. Those were VA people, I don't know if it's the same in civilian medicine.
I apologize for the joke and uninformed answer. A grownup will be along presently with a qualified answer, I'm sure.