BPD and PTSD often occur together, can have some of the same symptoms and may have similar causal factors. Both disorders are believed most likely to occur in those who have lived through traumatic circumstances, such as domestic violence, abuse, rape, war, or accidents. People who experience such traumatic events early in life are considered most likely to develop borderline personality disorder (BPD), especially if the trauma was prolonged, as in the case of domestic violence or child abuse. People who experience singular or prolonged psychological trauma later in life are believed more likely to develop post-traumatic stress disorder (PTSD). People with BPD may be more likely to develop PTSD in response to psychological trauma, and experts believe that BPD and PTSD occur together frequently.
According to studies, more than half of those with BPD also suffer from PTSD. BPD and PTSD may occur together because the early-life traumas that contribute to BPD may make it harder for these patients to cope with traumatic events later in life. People with BPD may have problems differentiating between the traumatic events of the past and the traumatic events of the future. When they experience trauma, they may be likely to remember or even feel as if they are reliving the trauma of the past. Some professionals speculate that some symptoms of BPD, including impulsive behaviors, recklessness, and a tendency to undertake volatile romantic relationships, may increase the BPD patient's chances of experiencing repeated psychological traumas later in life.
The symptoms of BPD typically make it hard for these patients to control their moods, form a viable self-image, get along with others, or trust others. As a result, BPD and PTSD may occur together because individuals with BPD often lack a healthy sense of self or a social support network, things that can be important when coping with trauma. People with BPD may also struggle with fears that they'll be abandoned, and may develop depression, anxiety, and paranoia.
Many of the symptoms of PTSD are similar to those of BPD. Just like people with BPD, people with PTSD often find themselves obsessed with the traumatic events of the past, reliving their memories and sometimes even feeling as if the events are occurring all over again. BPD and PTSD can both cause people to remain hyper-alert for signs of danger in the environment, so that these people may never feel safe, no matter where they are. Both disorders can cause mood swings, anger management problems, depression, anxiety, impulsive behavior, and suicidal ruminations.