Different mental illnesses face stigma: https://clinpsychsite.wordpress.com/2017/03/11/bipolar-schizophrenia-stigma/
"Depression, that's one thing-
lot of people have depression,
and they're not crazy.
That's mental illness-
the psychos, the nut cases, the incurably insane,
the muttering bag ladies and bums, the freaks.
So I take my meds,
and don't accept the name for what I have."
-"Madness: A Bipolar Life" by Marya Hornbacher
This quote shows that there are different forms of stigma for different mental illnesses. Depression is not stigmatized the same way bipolar disorder or schizophrenia is. If anything, it isn't taken seriously enough. Some people just think it is sadness and that the patient isn't trying hard enough to be happy. Sadness is something that everyone can relate to, so depression doesn't face the same stigma.
What makes bipolar disorder and schizophrenia more stigmatized may be the lack of education for the general public. Bipolar is often associated with out-of-control, impulsive, even violent, behaviors. Schizophrenia is linked to psychotic behavior. Not everyone with bipolar disorder is violent, and not everyone with schizophrenia is psychotic. We need to #endthestigma and spread the knowledge!
Even those who have the illness may believe the stigma. This is especially dangerous. This may lead to noncompliance with treatment or medication or therapy. Marya Hornbacher didn't want to accept that she was "mentally ill" because she associated that with being "crazy". Accepted that you are mentally ill is hard enough without facing the stigma... the stigma makes it even more challenging to get help.