This dissertation contributes to the literature on fathers’ parenting in families with young children using longitudinal, hormonal, and observational data. The results in Chapter 2 demonstrated... Show moreThis dissertation contributes to the literature on fathers’ parenting in families with young children using longitudinal, hormonal, and observational data. The results in Chapter 2 demonstrated that fathers’ hostile and harsh behaviors were related to children’s bullying behavior in elementary school, whereas the effect of the mothers’ behavior was less pronounced. In Chapter 3, the results suggested that fathers’ testosterone is beneficial for the quality of fathers’ parenting (i.e., sensitivity) when fathers’ testosterone reacts in the expected direction given the context of the father-child interaction (i.e., a decrease during a harmonious interaction and an increase during a challenging interaction). The results in Chapter 4 unexpectedly showed that fathers’ sensitivity was largely independent of varying gender-typed contexts. Chapter 5 provided evidence for a specific role of religious fathers, but not mothers, in communicating implicit gender messages and in turn the development of children’s gender attitudes. The most important take-away from this dissertation is that fathers cannot be ignored in child developmental and parenting research, and consequently also in child and family interventions. Show less
In the present study we measured the concentrations of cortisol, thyroid hormones, testosterone, and GABA (gamma aminobutyric acid) in am blood plasma samples of combatants with an at least 10 year... Show moreIn the present study we measured the concentrations of cortisol, thyroid hormones, testosterone, and GABA (gamma aminobutyric acid) in am blood plasma samples of combatants with an at least 10 year history of military psychological trauma (N = 74) divided in groups that either suffer from post-traumatic stress disorder (PTSD) (N = 37) or are resistant (N = 37) as well as in a control group without traumatic experience in the anamnesis, (N = 34). PTSD symptoms were assessed using the Clinician-Administered PTSD Scale (CAPS). The results show that the am blood cortisol levels of individuals that were exposed to war zone experiences irrespective susceptibility for or resistance to PTSD were significantly higher than the values observed in the controls. Testosterone levels in PTSD patients differed neither from that observed in PTSD resistant nor control groups. In the resistant group testosterone levels were however significantly higher than in controls. The level of all thyroid hormones did not differ between the study groups. GABA level was significantly lower in the PTSD group compared with healthy controls. In the resistant group blood GABA levels were not significantly different from either PTSD patients or controls. In conclusion, the current data show that cortisol and to some extent testosterone may serve as biomarker of war zone stress per se, even if trauma was experienced at least ten years before, rather than of only PTSD or resistance to PTSD. GABA, in contrast, can be considered a potential marker of the protracted nature of PTSD. Show less
Background: Hypoandrogenic men showed a higher prevalence of major depressive disorder (MDD), which could be ascribed to overlapping symptoms such as sexual dysfunction, or additionally to core... Show moreBackground: Hypoandrogenic men showed a higher prevalence of major depressive disorder (MDD), which could be ascribed to overlapping symptoms such as sexual dysfunction, or additionally to core emotional symptoms such as sadness and anhedonia. We examined whether androgen levels 1) differ between men with and without MDD cross-sectionally, 2) are associated with an elevated risk for onset of MDD prospectively, and 3) associate with all individual MDD symptoms, or only with hypogonadism overlapping symptoms. Methods: In 823 men (mean age 43.5 years), baseline plasma levels of total testosterone, 5 alpha-dihydrotestosterone (5 alpha-DHT), and androstenedione were determined with liquid chromatography-tandem mass spectrometry, and dehydroepiandrosterone-sulphate (DHEAS) and sex hormone binding globulin with radioimmunoassay, whereas free testosterone was calculated. MDD status was assessed at baseline and after two years using structured interviews and individual MDD symptoms were self-rated at baseline, and after one and two years. Results: None of the androgen levels were associated with current or onset (incidence or recurrence) of MDD. Free testosterone was only inversely associated with interest in sex. Also, androstenedione and DHEAS were positively associated with some individual MDD symptoms, and 5 alpha-DHT levels showed non-linear associations (both with low and high levels) with MDD symptom severity and several individual MDD symptoms. Conclusions: These results support the idea that circulating androgens synthesised by the testes are of limited clinical relevance to MDD in adult men, but levels of androstenedione, DHEAS and 5 alpha-DHT may be associated with some individual MDD symptoms. Show less
The onset of adolescence in humans is marked by hormonal changes that give rise to secondary sexual characteristics, noted as puberty. It has, however, proven challenging to unravel to what extent... Show moreThe onset of adolescence in humans is marked by hormonal changes that give rise to secondary sexual characteristics, noted as puberty. It has, however, proven challenging to unravel to what extent pubertal changes may have organizing effects on the brain beyond chronological age, as reported in animal studies. The present longitudinal study aimed to characterize the unique effects of age and puberty on subcortical brain volumes and included three waves of data collection at two-year intervals and 680 T1-weighted MRI scans of 271 participants (54% females) aged between 8 and 29 years old. Generalized additive mixed model procedures were used to assess the effects of age, self-report pubertal status and testosterone level on basal ganglia, thalamus, hippocampus, amygdala and cerebellum gray matter volumes. We observed age-related increases in putamen and pallidum volumes, and decreases in accumbens and thalamus volumes, all show larger volumes in boys than girls. Only the cerebellum showed an interaction effect of age by sex, such that males showed prolonged increases in cerebellar volume than females. Next, we showed that changes in self-report puberty status better described developmental change than chronological age for most structures in males, and for caudate, pallidum and hippocampal volumes in females. Furthermore, changes in testosterone level were related to development of pallidum, accumbens, hippocampus and amygdala volumes in males and caudate and hippocampal volumes in females. The modeling approach of the present study allowed us to characterize the complex interactions between chronological age and pubertal maturational changes, and the findings indicate puberty unique changes in brain structure that are sex specific. Show less
Peer, J.M. van; Enter, D.; Steenbergen, H. van; Spinhoven, P.; Roelofs, K. 2017
Testosterone plays an important role in social threat processing. Recent evidence suggests that testosterone administration has socially anxiolytic effects, but it remains unknown whether this... Show moreTestosterone plays an important role in social threat processing. Recent evidence suggests that testosterone administration has socially anxiolytic effects, but it remains unknown whether this involves early vigilance or later, more sustained, processing-stages. We investigated the acute effects of testosterone administration on social threat processing in 19 female patients with Social Anxiety Disorder (SAD) and 19 healthy controls. Event-related potentials (ERPs) were recorded during an emotional Stroop task with subliminally presented faces. Testosterone induced qualitative changes in early ERPs (<200 ms after stimulus onset) in both groups. An initial testosterone-induced spatial shift reflected a change in the basic processing (N170/VPP) of neutral faces, which was followed by a shift for angry faces suggesting a decrease in early threat bias. These findings suggest that testosterone specifically affects early automatic social information processing. The decreased attentional bias for angry faces explains how testosterone can decrease threat avoidance, which is particularly relevant for SAD. Show less
Previous research has found an association between a smaller cerebellar volume and higher levels of neuroticism. The steroid hormone testosterone reduces stress responses and the susceptibility to... Show morePrevious research has found an association between a smaller cerebellar volume and higher levels of neuroticism. The steroid hormone testosterone reduces stress responses and the susceptibility to negative mood. Together with in vitro studies showing a positive effect of testosterone on cerebellar gray matter volumes, we set out to explore the role of testosterone in the relation between cerebellar gray matter and neuroticism. Structural magnetic resonance imaging scans were acquired, and indices of neurotic personality traits were assessed by administering the depression and anxiety scale of the revised NEO personality inventory and Gray’s behavioural avoidance in one hundred and forty-nine healthy volunteers between 12 and 27 years of age. Results demonstrated an inverse relation between total brain corrected cerebellar volumes and neurotic personality traits in adolescents and young adults. In males, higher endogenous testosterone levels were associated with lower scores on neurotic personality traits and larger cerebellar gray matter volumes. No such relations were observed in the female participants. Analyses showed that testosterone significantly mediated the relation between male cerebellar gray matter and measures of neuroticism. Our findings on the interrelations between endogenous testosterone, neuroticism and cerebellar morphology provide a cerebellum-oriented framework for the susceptibility to experience negative emotions and mood in adolescence and early adulthood. Show less
Adolescence, defined as the transition phase between childhood and adulthood, is a time of many physical, cognitive and social-emotional changes. It is a natural time of exploring, thrill seeking,... Show moreAdolescence, defined as the transition phase between childhood and adulthood, is a time of many physical, cognitive and social-emotional changes. It is a natural time of exploring, thrill seeking, and for eventually setting long-term goals and aspirations. One of the most prominent findings is that adolescents take more risks than children or adults. The focus of this thesis is on adolescent risk taking behavior. The goal is to identify individual difference factors that are related to risk taking behavior and assess how these variables change over development. Adolescence is associated with major changes in hormonal levels, brain function and social environment. In this thesis it is tested how changes in pubertal development, brain function and social environment together influence real life risk taking. The studies in this thesis show that neural responses to rewards in the striatum are elevated during adolescence. This response is influenced by chronological age, pubertal development, personality and the social context. Importantly, the striatum response to rewards is related to real life risk taking behavior and therefore has functional relevance. The results of this thesis provide vital insight in the complex relationship between reward processing and real life risk taking behavior. Show less
The overall aim of the studies presented in this dissertation is to provide insight in the differences and similarities between mothers' and fathers' parenting practices. Further, this... Show moreThe overall aim of the studies presented in this dissertation is to provide insight in the differences and similarities between mothers' and fathers' parenting practices. Further, this dissertation examines the effect of biological factors (i.e., parental sex hormones) and child factors (i.e., gender, age, and birth order) on parenting behavior of mothers and fathers. In Chapter 2 differences between mothers and fathers with respect to parental sensitivity and nonintrusiveness are studied, also examining child gender and birth order. Further, in Chapter 3 the effect of child age and birth order on mothers' and fathers' sensitivity and nonintrusiveness is examined longitudinally. Chapter 4 focuses on the association between sex hormones (i.e., testosterone) and parental sensitivity and nonintrusiveness of mothers and fathers towards their two young children. In Chapter 5 differences between mothers' and fathers' discipline strategies towards their firstborn and second-born children are examined, also taking into account child gender. Finally, in Chapter 6 the main findings and implications of the studies presented in this dissertation are discussed and suggestions for future research are made. Show less
