A: For all psychological disorders, there are certain criteria that have to be met. These are spelled out clearly in the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the guide most clinicians use in the United States. For instance, to be given a certain diagnosis, the client might have to display 6 of 10 possible symptoms, but these symptoms have to cause impairment or distress to be given a formal diagnosis.
Some Personality Disorders are similar and are thus divided into three clusters: A, B, or C. The two disorders you mention are both in cluster B so they share some common features. If someone displays some features of a Personality Disorder, but not enough to meet the diagnostic criteria, a clinician might use the terminology of displaying “traits.”
A person can be diagnosed with more than one Personality Disorder and could also be diagnosed with another disorder, such as depression or PTSD. The only way to know if you have a particular disorder is to be evaluated by a mental health professional.
All the best,
Dr. Holly Counts