What are the causes of borderline disorder?

The causes of the disease are not clear for sure. Presumably, a blend of genetic factors and life experiences comes into play when a borderline personality emerges. As with other psychiatric illnesses, the development can be traced in a bio-psycho-social model.

Not out of the blue

Mental disorders, like physical illnesses, have certain causes and do not just fall from the sky. Only it is often not as clear and unequivocal as e.g. a bladder infection that can be contracted if you sit too long on a cold bench; or like the athlete's foot after visiting the swimming pool.

Mental illness usually develops over a long period of time from a whole bunch of different causes. In psychology, models are used to illustrate this complex genesis.

At the same time, the so-called bio-psycho-social model has emerged as decisive for all psychiatric illnesses. It states that the following elements, each with a different weighting, are involved in their formation:


The biological factors are pathological changes in the physical area, which are often measurable and representable. These include genetic systems, but also inflammatory, malignant or aging processes.

Especially with the borderline personality disorder one starts from a rather large genetic influence. However, individual genes that can be classified as mental illness have not yet been identified. A twin study merely provided evidence of a connection. However, the evidence of twins is rather difficult, as they usually grow up together in the same environment and are thus exposed to the same environmental factors.

Various studies also show a disturbed communication between brain areas, which are important for emotional processing. Changes in brain areas and brain metabolism are also discussed. However, there is still a great need for research here.


The respective predisposition and character of the personality plays an essential role in the development of mental illnesses. So there are more quiet and withdrawn people or on the contrary the extroverted, communicative types. They are more susceptible or resistant to different diseases.

"Borderliners" are often self-conscious people who have not developed a clear self-image and self-esteem. In their behavior, they can be tempers at times, only to withdraw completely.


The experiences that a person makes during his life with other people shape him / her sustainably. In particular, the family ties in childhood and youth play a role.

In the life story of "borderliners" unfavorable conditions can often be found, especially in childhood through problematic relationships. Often sufferers have traumatic experiences such as abuse, violence or neglect made in their environment. Homesizing and school difficulties such as marginalization and bullying can also play a role.

However, not all children who have had such experiences later develop a borderline disorder. They must have developed their own defense mechanisms in order to distance themselves from the experiences.

It is important that the therapist works with the person concerned to work out the background of his suffering. There are a variety of psychological tactics and exercises to uncover the mostly unconscious mechanisms in the background. Often it is very helpful and relieving to understand why in some situations you always react in a certain way or why many things just never succeed. This insight provides the key to the right therapeutic approaches.

Authors: Dr. med. Julia Hofmann, Eva Bauer (doctor)