Patterns of cortisol and DHEA secretion and relationships with attachment style and psychosocial variables in female adolescents: a developmental psychopathology approach

This programme of research used a developmental psychopathology approach to investigate females across the adolescent period. A two-sided story is presented; first, a study of neuroendocrine and psychosocial parameters in a group of healthy female adolescents (N = 63), followed by a parallel study of female adolescents with anorexia nervosa (AN) (N = 8). A biopsychosocial, multi-method measurement approach was taken, which utilised self-report, interview and hypothalamic-pituitary-adrenocortical (HPA) axis measures. Saliva samples for the measurement of cortisol and DHEA were collected using the best-recommended methodology: multiple samples over the day, strict reference to time of awakening, and two consecutive sampling weekdays. The research was adolescent-orientated: specifically, by using creative and ageappropriate strategies to ensure participant adherence to protocol, as well as more generally by adopting various procedures to facilitate engagement with the research process. In the healthy females mean (± SD) age 13.9 (± 2.7) years, cortisol and DHEA secretion exhibited typical adult-like diurnal patterns. Developmental markers of chronological age, menarche status and body mass index (BMI) had differential associations with cortisol and DHEA secretory activity. The pattern of the cortisol awakening response (CAR) was sensitive to whether participants had experienced first menses, but not to chronological age or BMI. Those who were post-menarche generally reached their peak point of cortisol secretion at 45 minutes post-awakening, in contrast to the pre-menarche group who were more evenly spread. Subsequent daytime cortisol levels were also higher in post-menarche females, and this effect was also noted for increasing age and BMI. Both morning and evening DHEA were positively associated with developmental markers. None of the situational or self-report psychosocial variables that were measured modulated any of the key findings regarding cortisol and DHEA secretion. The healthy group of girls were within age-appropriate norms for all the self-report measures used, however just under half of this group were insecurely attached (as assessed by interview). Only attachment style was associated with neuroendocrine parameters. In particular, those with an anxious insecure style exhibited a higher awakening sample (levels were 7.16 nmol/l, 10.40 nmol/l and 7.93 nmol/l for secure, anxious and avoidant groups, respectively) and a flatter CAR (mean increases over the awakening period were 6.38 nmol/l, 2.32 nmol/l and 8.61 nmol/l for secure, anxious and avoidant groups, respectively). The afore-mentioned pattern is similar to that consistently associated with psychological disorder in adults, and so this may be a pre-clinical vulnerability factor for subsequent mental health problems. A group of females with AN, mean (± SD) age 15.1 (± 1.6) years, were recruited from a specialist residential clinic and compared to the above group of healthy control (HC) female adolescents. A general picture of cortisol and DHEA hypersecretion was revealed in those with AN. The mean (± SD) change exhibited in cortisol levels over the 30 minute post-awakening period was 7.05 nmol/l (± 5.99) and 8.33 nmol/l (± 6.41) for HC and AN groups, respectively. The mean (± SD) evening cortisol level for the HC girls was 1.95 nmol/l (± 2.11), in comparison to 6.42 nmol/l (± 11.10) for the AN group. Mean (± SD) morning DHEA concentrations were 1.47 nmol/l (± 0.85) and 2.25 nmol/l (± 0.88) for HC and AN groups, respectively. The HC group’s mean (± SD) concentration of 12 hour DHEA was 0.55 nmol/l (± 0.46) and the AN group’s mean level was 0.89 nmol/l (± 0.90). This adrenal steroid hypersecretion evidenced by the AN group was not associated with BMI or eating disorder symptomatology. Insecure attachment characterised by fearfulness and anger was most apparent; a style which was unparalleled in the healthy group of female adolescents. The causal directions of the AN group findings remain unclear. Examining some of the participants with AN as case studies one year post-discharge from the clinic illustrated that for one participant who was recovered, in terms of returning to ordinary school life and no longer exhibiting clinical levels of eating disorder symptomatology, her CARs were no longer inconsistent over sampling days and her DHEA levels were also now generally comparable to the healthy control group. For another participant who had not recovered from her AN one year later, the profile of her CAR continued to be inconsistent over sampling days and her DHEA concentrations over the diurnal period were significantly higher in comparison to the healthy control group. In its entirety, this work’s unique contribution lies in its consideration of methodological and developmental issues specifically pertaining to adolescents. Findings also contribute to knowledge of AN and understanding of vulnerability factors, and how these may be used to develop interventions dedicated to improving adolescent health.

River Sediment Sampling and Environment Quality Standards: A Case Study of the Ravensbourne River

Sediment is a major sink for heavy metals in river, and poses significant risks not only to river quality but also to aquatic and benthic organisms. At present in the UK, there are no mandatory sediment quality standards. This is partly due to insufficient toxicity data but also due to problems with identification of appropriate sediment monitoring and analytical techniques. The aim of this research was to examine the sampling different river sediment compartments in order to monitor compliance with any future UK sediment environmental quality standards (EQS). The significance of sediment physical and chemical characteristics on sampling and analysis was also determined. The Ravensbourne River, a tributary of the River Thames located in the highly urbanised South Eastern area of London was used for this study. Sediment was collected from the bed using the Van Veer grab, the bank using hand trowel, and from the water column (suspended sediment) using the time integrated suspended tube sampler between the period of July 2010 and December, 2011. The result for the total metal extraction carried out using aqua regia found that there were no significant differences in the metal concentrations retained in the different compartments by the <63μm sediment fraction but there were differences between the 63μm-2mm fractions of the bed and bank. The metal concentration in the bed, bank and suspended sediment exceeded the draft UK sediment quality guidelines. Sequential extraction was also carried out to determine metal speciation in each sediment compartment using the Maiz et al. (1997) and Tessier et al. (1979) methods. The Maiz et al. (1997) found over 80% of the metals in each sediment compartment were not bioavailable, while Tessier et al. (1979) method found most of the metals to be associated with the Fe/Mn and the residual phase. The bed sediment compartment and the <2mm (<63μm + 63μm-2mm) fraction appears to be the most suitable sediment sample for sediment monitoring from this study.