The causes of BPD are still unknown but it is thought that genetic, family and social factors play a role. Biologically, individuals with BPD are more likely to have abnormalities in the size and functioning of the hippocampus, the amygdala, and the frontal lobes of the brain which are understood to regulate emotions. These are however, not reliable predictors of BPD.
BPD is often accompanied by other lifestyle disorders like a substance abuse. In such cases it is sometimes difficult to say which disorder caused the other. Other disorders associated with BPD are eating disorders especially in women. In adolescents, BPD tends to occur with schizotypal and passive- aggressive personality disorders. People who exhibit antisocial behavior are more likely to have BPD as do people with bi-polar disorder.
Certain people are at a higher risk of developing BPD. Some of these are: