Borderline 

Borderline personality disorder (BPD) is a serious mental illness that causes unstable moods, behavior, and relationships. It usually begins during adolescence or early adulthood.
Most people who have BPD suffer from:
Problems regulating their emotions and thoughts
Impulsive and sometimes reckless behavior
Unstable relationships
Incidence
BPD affects 5.9% of adults (about 14 million Americans) at some time in their life
BPD affects 50% more people than Alzheimer’s disease and nearly as many as schizophrenia and bipolar combined (2.25%).
BPD affects 20% of patients admitted to psychiatric hospitals
BPD affects 10% of people in outpatient mental health treatment
Prognosis
Research has shown that outcomes can be quite good for people with BPD, particularly if they are engaged in treatment. With specialized therapy, most people with borderline personality disorder find their symptoms are reduced and their lives are improved. Although not all the symptoms may ease, there is often a major decrease in problem behaviors and suffering. Under stress, some symptoms may come back. When this happens, people with BPD should return to therapy and other kinds of support.
Many individuals with BPD experience a decrease in their impulsive behavior in their 40’s.
The Diagnosis
Overview
A mental health professional experienced in diagnosing and treating mental disorders-such as a psychiatrist, psychologist, clinical social worker, or psychiatric nurse-can detect BPD based on
An in-person interview to discuss symptoms
Input from a family or close friend that adds to the information provided by the individual coming for treatment.
A careful and thorough medical exam can help rule out other possible causes of symptoms.