Bipolar Disorder (BD) and Borderline Personality Disorder (BPD) have common clinical features in the diagnosis. Factors included in the development and neurobiology of BD and BPD, as early stress and neuroendocrine markers, may represent indicators to difference them.

Assess early life stress and HPA axis associated with diagnosis of BD and BPD.

Evaluation of 26 subjects, subdivided in groups of BD and BPD diagnosis, and health controls. Diagnostic was confirmed by Structured Clinical Interview for Axis I and II Disorders; early life stress was investigated by Childhood Trauma Questionnaire and classified in subtypes physical abuse, sexual abuse, emotional abuse, physical neglect and emotional neglect. HPA axis was assessed by cortisol plasmatic levels.

Early life stress is significantly higher in BD and, especially, BPD patients compared to controls, as well emotional abuse and neglect types; however, it didn’t differentiate the clinical groups. Cortisol levels was lower in BD group in relation of BPD, although without a significantly difference. In BPD group, cortisol levels was positively correlated to sexual abuse severity; in the same way, in BD group cortisol levels was correlated positively to emotional neglect.

Early life stress is more prevalent and severity in patients than in health controls, independently to diagnosis. BPD presents early life stress more severity compared to BD group. Moreover, cortisol levels was lower in BD. Cortisol levels was positively correlated to subtypes of early life stress and severity. This study indicates a promissory field to be better differentiate BD and BPD.