Creation and validation of the 8-Item Brief Emotional Eating Scale (BEES-8, version 1.0) in youth and adults.

Testosterone is an important sex hormone present in both sexes. In females, its concentrations are lower than in males, and it is produced by the ovaries and the adrenal glands. Like other neurosteroids, testosterone can also be synthesized within the nervous system []. The initial idea to investigate testosterone in borderline personality disorder (BPD) stemmed from three lines of observation. First, neuroendocrinology largely agrees that different hormone systems are closely associated and interconnected. While the hypothalamus pituitary adrenal (HPA) axis has received a lot of attention, the hypothalamic pituitary gonadal (HPG) axis has been largely neglected, especially in BPD. Second, in clinical psychiatric research testosterone has been repeatedly linked to affective symptoms, like depressive mood and anxiety, and showed effects on cognition and social behavior. Thirdly, on the level of reproductive endocrinology, women with BPD are frequently observed to suffer from polycystic ovary syndrome (PCOS), a hormonal disorder associated with elevated androgen levels. This overlap suggests that hormonal imbalances linked to testosterone, particularly those influencing mood and reproductive function, may contribute to the symptomatology of BPD. A large amount of studies investigated the function of the hypothalamus pituitary adrenal (HPA) axis in stress-related mental disorders such as major depressive disorder (MDD), post-traumatic stress disorder (PTSD) and borderline personality disorder (BPD). Findings suggest partly overlapping and partly disorder-specific patterns of HPA axis function, as well associations with cognitive functions within disorders [, , ]. In BPD, meta-analytic evidence suggests enhanced basal cortisol release and blunted cortisol reactivity to psychosocial stress [,]. Stress and cortisol then effect cognition, and can impact and impair learning, memory formation [], and social cognition []. In addition to an activation of the HPA axis during stress, several studies demonstrate stress-associated testosterone increase [,], particularly in the Trier Social Stress Test (TSST) []. Importantly, while the reciprocal relationship between HPA and HPG axis hormones is undisputed, its exact mechanisms are only incompletely understood []. Activation of the HPA axis can have both, suppressing and stimulatory effects on HPG axis function. Sex hormones like testosterone and estradiol can mediate the stress response via influencing glucocorticoid secretion and feedback regulation. Testosterone, in contrast to estrogens, has been shown to inhibit HPA axis function []. Importantly, the behavioral effects of testosterone often depend on cortisol concentrations. This non-linear interaction between both axes has been acknowledged by the dual-hormone hypothesis []. In clinical studies, testosterone levels have been repeatedly related to depressive mood states and anxiety, with most studies suggesting that low testosterone levels increase the risk of these mental disorders []. In this context, elderly men have been investigated most frequently, suggesting that in this group hypogonadism (i.e., lowered production of gonadal hormones, particularly testosterone) was positively associated with psychological complaints []. However, in a large cohort study, lower testosterone was primarily associated with mental disorders in women [], and evidence shows higher levels of testosterone in women with severe MDD []. Taken together, while the influence of testosterone on mental health is strongly supported, neither the direction nor the exact mechanism of this influence is yet clear, as important factors like sex and age, as well as their interaction, have not received systematic investigation.