What is the difference between personality disorder and other types of mental illness? From Personality disorders - Mayo Clinic:


  A personality disorder is a type of mental disorder in which you have a rigid and unhealthy pattern of thinking, functioning and behaving. A person with a personality disorder has trouble perceiving and relating to situations and people. This causes significant problems and limitations in relationships, social activities, work and school.


From Mental illness - Mayo Clinic:


  Mental illness, also called mental health disorders, refers to a wide range of mental health conditions — disorders that affect your mood, thinking and behavior. Examples of mental illness include depression, anxiety disorders, schizophrenia, eating disorders and addictive behaviors.


So I understand the personality disorders are more about having a rigid and unhealthy pattern of thinking, while mental illness in general is more about mood. However, in my understanding that mood is just automatic thinking that stems from past experience, which is no differ than personality disorder. The CBT approach, which is again fixing incorrect automatic thoughts, seems to be successful in working with both of them.

So is there any actual difference between them? Or is that personality disorder just an extreme version of mental illness, in which the belief is more systematic (world view or belief system I would say)?



A minor and quick to answer question: why is personality disorder has the "personality" in its name?
There may not be one: 


  it is impossible to conclude with confidence that personality disorders are, or are not, mental illnesses; there are ambiguities in the definitions and basic information about personality disorders is lacking.


https://www.ncbi.nlm.nih.gov/pubmed/11823318/

Mental illness in general isn’t about mood, either. Mood only covers mood disorders, but the DSM and ICD contain other conditions too: autism, schizophrenia, etc. 

Mental illnesses also have biological components, they’re not solely disorders of thought patterns formed over time.