After being told I was simply depressed and anxious I finally received the correct diagnosis of Bipolar disorder after only waiting until I was 25 years old. As you do with pysicial illnesses you should also GET A 2ND OPINION for a loved one or yourself. A diagnosis can mean the difference between functionality and income to being in a bed 24x7 and nearly homeless.
Go with your gut. If the diagnosis doesn't seem to fit you then it's likely very very wrong. I wish I had done this, I could have saved those late teen years of ***l and might have had a LIFE into my early 20s.