Associations between age and cortisol awakening response in patients with borderline personality disorder

Patients with borderline personality disorder (BPD) often display increased stress vulnerability, which may be linked to altered hypothalamus-pituitary-adrenal (HPA) axis functioning. Corresponding deviations of the cortisol awakening response (CAR) are presumed to mirror maladaptive neuroendocrine processes, which may explain why CARs are increased compared to healthy controls (HC). Prior research speculated that these alterations may be caused by early life stress and/or chronic stress related to the ongoing burden of the disorder. Yet, it remains to be investigated how BPD influences CAR in the course of development. Therefore, the current study examined CAR in female adolescents and adults with BPD compared to HC with a particular focus on associations with age. These potential associations were especially focused, as it was hypothesized that the CAR would be even more elevated (i.e., higher) in older individuals with BPD. CAR was assessed in 54 female individuals with BPD (aged 15-40 years) and 54 sex-, age-, and intelligence-matched HC (aged 15-48 years). Group differences were investigated and analyses of covariance using age as continuous predictor were performed to analyze potential developmental associations with CAR alongside BPD-specific effects. Pearson's correlations were calculated to examine associations between CAR and age. Analyses were repeated with potential confounders as control factors. Results not only demonstrated increased CARs in female individuals with BPD compared to HC but demonstrated elevated CARs with increasing age in BPD individuals exclusively. Effects remained stable after controlling for potential confounders. Thereby, findings suggest that endocrine alterations in BPD may reinforce with increasing age and BPD chronicity.