Nearly 73% meet the criteria for a substance use disorder, and about 40% for PTSD. It is noteworthy that less than half of the participants with BPD in this study presented with PTSD, a prevalence similar to that reported in an earlier study. The finding that less than half of patients with BPD experience PTSD during their lives challenges the theory that BPD and PTSD are the same disorder.There are marked sex differences in the types of comorbid conditions a person with BPD is likely to have—a higher percentage of males with BPD meet criteria for substance-use disorders, while a higher percentage of females with BPD meet criteria for PTSD and eating disorders. In one study, 38% of participants with BPD met the criteria for a diagnosis of ADHD. In another study, 6 of 41 participants (15%) met the criteria for an autism spectrum disorder (a subgroup that had significantly more frequent suicide attempts).Regardless that it is an infradiagnosed disorder, a few studies have shown that the "lower expressions" of it might lead to wrong diagnoses. The many and shifting Axis I disorders in people with BPD can sometimes cause clinicians to miss the presence of the underlying personality disorder. However, since a complex pattern of Axis I diagnoses has been found to strongly predict the presence of BPD, clinicians can use the feature of a complex pattern of comorbidity as a clue that BPD might be present.
Transient, stress-related paranoid or severe dissociative symptoms.Overall, the most distinguishing symptoms of BPD are pervasive patterns of instability in interpersonal relationships and self-image, alternating between extremes of idealization and devaluation of others, along with varying moods and difficulty regulating strong emotional reactions. Dangerous or impulsive behavior is also correlated with the disorder. Other symptoms may include feeling unsure of ones identity, morals, and values; having paranoid thoughts when feeling stressed; depersonalization; and, in moderate to severe cases, stress-induced breaks with reality or psychotic episodes. Individuals with BPD often have comorbid conditions, such as depressive and bipolar disorders, substance use disorders, eating disorders, post-traumatic stress disorder, and attention-deficit/hyperactivity disorder. Emotions
People with BPD may feel emotions with greater ease and depth and for a longer time than others do. A core characteristic of BPD is affective instability, which generally manifests as unusually intense emotional responses to environmental triggers, with a slower return to a baseline emotional state. According to Marsha Linehan, the sensitivity, intensity, and duration with which people with BPD feel emotions have both positive and negative effects. People with BPD are often exceptionally enthusiastic, idealistic, joyful, and loving, but may feel overwhelmed by negative emotions (anxiety, depression, guilt/shame, worry, anger, etc. ), experiencing intense grief instead of sadness, shame and humiliation instead of mild embarrassment, rage instead of annoyance, and panic instead of nervousness. Studies have shown that borderline patients experience chronic and significant emotional suffering and mental agony.People with BPD are also especially sensitive to feelings of rejection, criticism, isolation, and perceived failure.