Borderline Personality Disorder is a mental health disorder that can cause a pattern of behavioral instability in interpersonal relationships, self-image, affections and varying moods. It is considered a borderline disorder, a “non-normal” modality of the personality to relate to the world and a state that can be considered pathological. A person with Borderline syndrome has symptoms such as impulsivity, distorted vision of himself/herself and others, fear of abandonment or being alone and aggressive and intense reactions. There may be varying periods of anger, depression and anxiety. And usually these last for days or even weeks.

The term "Borderline Personality Disorder" was used for the first time in 1884 and has since gone through several concept revisions over the years. Originally, the term "Borderline" referred to a group of patients who lived on the edge of sanity (hence the term "borderline"), that is, on the “border” between neurosis and psychosis. Some authors at the time used this diagnosis when there were severe neurotic symptoms in patients. It was only in the 1980s that the diagnosis of the disease became more accurate. Until then, many doctors mistakenly believed that a person's personality was immutable. 

Borderline disorder can begin in adolescence or adulthood. Among its characteristics, the following stand out: 

● Instability of interpersonal relationships 

● Self-image instability 

● Instability of affections 

● Impulsivity

From the characteristics of the disorder, a person with borderline may develop symptoms throughout life such as: 

● Emotional instability 

● Excessive affective deregulation 

● Intense and polarized feelings like “everything is great and everything is terrible” or “I adore you and I hate you” 

● Anguish of abandonment 

● Perception of being invasive 

● Impulsivity 

● Self-injury 

● Boredom 

● Feeling of emptiness 

● Suicidal thoughts 

● Stress 

● Rage 

● Impatience 

● Frequent mood swings 

● Reactivity of mood (episodic dysphoria, irritability or intense anxiety lasting generally a few hours and only rarely more than a few days) 

● Pattern of unstable and intense interpersonal relationships, characterized by the alternation between extremes of idealization and devaluation 

● Disturbance of identity: marked and persistent instability of self-image or self-perception ● Transient paranoid ideation associated with intense stress or dissociative symptoms.

The causes and factors involved in the emergence of Borderline Personality Disorder are diverse. Genetic predisposition and even early emotional experiences and environmental factors, especially in childhood, with emphasis on situations of traumatic abuse and neglect can favor the development of this disorder. In general, talking to the patient about the diagnosis is the preferred approach for most specialists. Questions that need to be asked are about suicidal thoughts, self-injurious acts, and thoughts about hurting others. The diagnosis is clinical, based on the patient's report and the physician's observations. 

Whenever a patient with Borderline Personality Disorder (BPD) has very distressing symptoms and/or reactions that can affect or hurt himself/herself or others, he/she should see a doctor. The same occurs when there is a suicide intention or even an attempt. In these cases, it is very important that the family and, especially, the therapists are aware of these thoughts, as they can help the diagnosis. Borderline Personality Disorder has been viewed as difficult to treat. However with recent improvement in understanding of this condition, newer evidence based treatments offer an improved quality of life . Thus making it possible to live with the disorder in a much milder way than previously thought. 

References: 

https://www.verywellmind.com/borderline-personality-disorder-meaning-425191#:~:text=History%20of%20%22Borderline%22%20in%20Borderline,borderline%20schizophrenia%22%20in% 20certain%20situations. 

https://www.nhs.uk/conditions/borderline-personality-disorder/ 

https://www.nami.org/About-Mental-Illness/Mental-Health-Conditions/Borderline-Personality-D isorder

https://www.nimh.nih.gov/health/topics/borderline-personality-disorder/index.shtml